CORTO MALTESE 65
Southampton Solent University
FACULTY OF TECHNOLOGY
BEng (Hons) Yacht and Powercraft Design
Giotto Guglielmo
PRELIMINARY DESIGN OF CORTO MALTESE
A 65 FEET IRC YACHT
Project supervisor: Giles Barkley
This project is submitted in part fulfillment of the Degree of Bachelor of Engineering with Honors in Yacht & Powercraft Design At The Solent University of Southampton In May 2009
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Abstract
This project is a preliminary design of an IRC compliant racing yacht, with particular focus on stability versus power to carry sails. It was learned that the weight and centres estimation, and the definition of hull parameters, were the most critical design aspects for this aim, and were developed. Preliminary estimates of aero-hydrodynamics and structural engineering characteristics were defined, but the much deeper understanding of a field specialist is required to take these further. The VPP software revealed itself to be a powerful tool in the preliminary definition of hull parameters.
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In the air there was an absolute calm, he felt only the noise of the regular roll of water along the hulls,
and the occasional gusts of wind that spread the sail
with dry and noisy lashes. Suddenly, the cry of the
lookout sailor broke that tranquillity.
He showed something, far, beyond the bow.
Hugo Pratt, Una balata del mare salato Ref21
Un romanzo EInaudi
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Nomenclature used
LWL: wetted length SAC: sectional area curve
LOA: over all length Cp: prismatic coefficient BWL: wetted breath TWS: true wind strength
Tc: canoe draft TWA: true wind angle
LCB: longitudinal centre of buoyancy AWS: apparent wind strength
Sr: slenderness ratio AWA: apparent wind angle
RM: righting moment VMG: velocity made good
WSA: wetted surface area Tk: keel draft
Rf: frictional resistance CL: Coefficient of lift
Rt: total resistance Ar: aspect ratio
RrD: residuary resistance Arg: geometric Ar
Rh: heel resistance Are: effective Ar
Ri: Induced resistance RA90: righting moment @ 90º
Di: Induced resistance IRC: International race comity
SA: sail area ORC: Offshore racing congress
Disp.: displacement in (Kg) DWL: datum water line
FN: Froude’s number
RN: Reynolds’s number
Bmt: transverse methacentric height
LCF: longitudinal centre of flotation
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1) Introduction
In the last ten years the world of racing yachts was more oriented on the Racer-Cruiser type of vessel as the IMS rating formulae was ruling those design. Nowadays it seems that owners and designers are more oriented on IRC (International Rating certificate) rating Rule, this is because IRC is a much simpler rule, it has less restrictions and compromise, allowing for better performance and on the contrary of IMS, this rating system allows a yacht to be competitive for longer time. This is why the IRC format is been chosen as a category for the 65 feet long vessel involved in the project. As it will be explained in the design requirement later on, the primary target are to produce an aggressive racer therefore the area on which the project will focus will be stability versus power to carry sail, weight saving, appendages configuration, sail plan configuration.
2) Design brief (Design requirement)
The project will involve the design of a sloop of 65 feet aggressively racing orientated that will comply with category A RCD regulation society rules. The vessel requirements are to be competitive in off - shore oceanic racing as well as around buoys regattas. The design should be capable of high performance with an all round attitude reaching speeds around 20 knots and above, therefore to allow more stability and more sail area, it will involve the use of a canting keel device, additional water ballast may be used in order to increase this aspect, additional focus on appendages resistance and sail plan. Regarding IRC handicap particular emphasis should be put in to pure performances purposes, The yacht is meant for winning the race in real time not compensated one, so no compromise here speed is what we are looking for!
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3) Methodology
The spiral
In order to meet the design requirement a sequence of 10 operation known as the Spiral will be taken as a guideline for a self learning process, substantially it can be seen as a step by step process starting from collected data going trough every single design step then after an analysis of the data obtained rerun the process again refining and optimizing the project parameters until the design meets the requirement criteria listed before.
There is the necessity to keep the design requirements in mind, in order to establish the point on which more research will be needed as well as the areas to focus on to produce more performance.
The process can be summarised in those steps (Remember this is an overall picture, some of the stages, development and theoretical extrapolation presented below will be studied and analyses later, on some more advanced circle of the spiral):
Collection of data from existing vessels
This is the starting point collecting data from existing vessel, analyse them using “Excel software” to obtain some first target parameter as a starting point for the design of the hull, sail area and various ratios (beam over length ec). The IRC Rule will also been used to define some limitations for the yacht characteristics and parameters. Keeping in mind that what one of the major target of the project is speed.
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Hull forms definition
Using the data extrapolated from a database of existing vessel some primary hull lines will be developed. Proceeding down the spiral the forms will be optimized (with the aid of specific software like “Max Surf”) to meet the requirements with particular focus: on producing a balance yacht able to perform well in all condition, the effect of beam on stability and wetted surface area and how this relate on upwind performance.
Keel and appendages design
In order to increase the capability of the vessel to carry sail power canting keel device is going to be taken in consideration. Aspect ratio, rudder and canard configuration as well as the generation of side force could be others areas of investigation. The use of additional water ballast may help to increase the stability hence power.
Sail Plan configuration
Comparing and analyse data from existing vessel, trying to achieve the bigger sail area allowed by the stability of the vessel. Huge sail plan imply structural features to be considered. The mast may be laminated from a male mould as one component saving weight (New technique). This is the engine that will allow the yacht to reach incredible speeds.
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General arrangement
In order to meet the requirement the arrangement needs to be simple and practical and as light as possible to save weight. The vessel will be equipped with 12 berths, one cooking station, a toilet installation, and navigation position.
Hull and deck scantling
Starting from some rough estimation of loads acting on the yacht and then refining by the use of scantling software. Focus on trying to save as much weight as possible. Particular attention must be paid on the structure holding the canting keel as well as the mast (huge sail plane bigger loads). This area of the project will comply with classification society rules as RCD ISO Standard category A.
Weights estimation
At the first step will be a rough estimation as well but as the spiral goes around some more plausible value should came out. As the vessel requires aggressive racing attitudes particular focus will be shown to try to keep the centre of gravity (VCG) as low as possible to increase righting moment and stability.
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Stability
Evaluation by the use of software as Hydromax stability will be a major aspect of the project due to the requirement of a power full sailing plan. Stability also complies with classification society rules.
Schedule
In order to organize better the time resources of the project, a Gantt chart is been produced This is just a preliminary schedule to help the author to pre plan the different stages in respect of time.
Conclusions
The project will involve areas of investigation in which the author have still little knowledge and lacks in experience therefore “technical” articles and reports will be used as useful sources of information. Regardless the above statement, following the procedures, stages and points, that were presented and listed in the small introduction above, will hopefully allow the designer to fulfil the requirement of the project with good results.
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Table of Contents Abstract ...... 2 Nomenclature used ...... 5 1) Introduction ...... 6 2) Design brief (Design requirement) ...... 6 3) Methodology ...... 7 The spiral ...... 7 Collection of data from existing vessels ...... 7 Hull forms definition...... 8 Keel and appendages design ...... 8 Sail Plan configuration...... 8 General arrangement ...... 9 Hull and deck scantling ...... 9 Weights estimation ...... 9 Stability ...... 10 Schedule ...... 10 Conclusions ...... 10 Chapter 1: Parametric studies ...... 14 1.1) Collection of data...... 14 1.2) Non dimensional design ratio...... 14 1.3) Preliminary dimensions ...... 16 1.4) Preliminary investigation...... 16 Chapter 2: Hull Design ...... 17 2.1) Hull length ...... 18 2.2) Froude’s number evaluation ...... 18 2.3) Waterline breadth investigation ...... 19 2.4) Mid ship section...... 22 2.5) Shear line and freeboard ...... 22 2.6) Bow shape ...... 23 2.7) Cp and LCB positioning ...... 23 Chapter 3: sail design...... 26 3.1) Configuration ...... 26 3.2) Sails ...... 27 3.3) Sail inventory...... 28 3.4) Balance ...... 29 Chapter 4: appendages design ...... 30 4.1) Canting keel fin ...... 32 4.2) Canards ...... 33 4.3) Rudders ...... 34 Chapter 5: structure...... 37 Introduction...... 37 Materials ...... 39 5.1) Hull ...... 40 5.1.a) panels ...... 40 5.1.b) Longitudinal stiffeners ...... 41 5.1.c) Conclusions ...... 42 5.2) Appendages ...... 43 5.1.a) Cariboni keel experience ...... 43 5.2.b) Rudder and Dagger boards...... 44 5.3) Mast & rigging...... 44
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Chapter 6: General arrangement ...... 46 6.1) Interiors ...... 46 6.2) Machinery and tanks ...... 47 6.3) Deck ...... 47 Chapter 7 Stability ...... 48 Chapter 8 Balance ...... 51 Chapter 9: VPP analysis ...... 52 Chapter 10) Schedule...... 55 Conclusions...... 56 References ...... 58 Appendix A...... A3 Drawing 1: Sail Plan ...... A3 Drawing 2: Interior...... A3 Drawing 3: Structure A ...... A3 Drawing 4: Scantlings ...... A3 Drawing 5: Deck Plan & profile ...... A3 Drawing 6: Interior Sections A ...... A3 Drawing 7: Interior Sections B ...... A3 Drawing 8: Interior Sections C ...... A3 Drawing 9: Mast & Details ...... A3 Drawing 10: Hull Lines ...... A3 Drawing 11: Balance...... A3 Drawing 12: Water Planes ...... A3 Drawing 13: Structural lay out (Rhino Render) ...... A3 Appendix B...... 63 Appendix C ...... 63 Appendix D...... A63 ......
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Chapter 1: Parametric studies
1.1) Collection of data
A parametric database was created containing yachts whose lengths ranged from 55 to 85 feet (Table 1 Appendix B). In order to meet the design requirement, this selection was focused on the latest IRC racing Yachts (as the Mills design “Allegre 68” Ref1). Regarding Oceanic performance some data were available from the more extreme and innovative vessel as the “VOR 70” and “Open 60” As well as some bigger IRC category 0 designs that have shown quite good attitude in rough sea state condition as in the “Rolex Sydney to Hobart yacht race” (ref2). The information resources were websites, books and magazines and some preliminary drawings that were available to the author. The accuracy of the data collected may differ from the actual boat parameters, some issues were found in defining hull parameters as BWL and ratios as Cp and LCB, therefore some have been estimated. Those values may lead to inaccuracies, especially in the dimensionless ratio obtained from the study that will be used to define the preliminary design parameters. Some useful data were extrapolated from drawings where it was possible, in order to get reliable LWL BWL Tc.
1.2) Non dimensional design ratio
Those data have been used to plot the following non – dimensional ratios vs. boat length (LWL) in order to establish the preliminary characteristic of the design:
LWL S • Slenderness ratio, r = 1 ∇ 3
• Waterline length/ Breath, LWL LWL /BWL = BWL € • Sail area / displacement ratio, sailingarea € SA,dispr = 2 ∇ 3
€
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• Ballast ratio, ballastmass B = R Δ (See figure 1, figure 2, figure 3, figure 4, Appendix B). €
Regarding the slenderness ratio, figure 1 shows that the data produce a nice fit for the regression line. Some sort of analysis can be done concerning the vessel requirement. It is believed that (Sr) should fit above the regression line, in order to have a light displacement yacht. Which will help in light winds performances as well as in buoy regattas where the boat will have higher accelerations resulting in higher speed coming out of a tack or a jibe. It also true that the canting keel device will make the yacht more stable and therefore is possible to have slender boat for the same righting moment (RM).
Figure 2 shows that the data are more widely spread from either side of the regression fit, especially the canting keels ones. There fore this graph was not really useful. Still some consideration can be gathered. It is true that (BWL) will have wide effect on the wetted surface area (WSA), the upwind performances and most off all the stability. For the particular requirement of the vessel it is believed that a beamier yacht will have more power to carry sail necessary for fast downwind runs. The increase in frictional drag Rf due to a bigger WSA and a loss in waterline symmetry (hence upwind performance) could eventually be overcome by increasing the sailing area.
Figure 3 shows a better correlation of the data and it can be seen that for a waterline length of 18.7 m the SA/disp. ratio should be around 49. However this is an average and it has been decided that the ratio of the design should be above the regression line. Indeed the higher the SA/disp. ratio the better the light air performances, so to overcome the penalties due to an increase in WSA.
The ballast ratio graph (Figure 4) shows a clear trend (especially the ck), which suggests a ballast ratio approximately equal to 0.54.
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From the above analysis, the following design ratios were set:
• Slenderness ratio = 7.71 • Waterline breath ratio = 5.1 • Sail area/displacement ratio = 50 • Ballast ratio = 0.54
1.3) Preliminary dimensions
Thanks to the parametric study the following dimensions were selected as a basis:
• Length overall (LOA) = 19.5m • Waterline length (Lwl) = 18.37m • Displacement = 13799kg (full load) • Ballast = 7400 kg • Sail area = 282 m²
1.4) Preliminary investigation
A preliminary weight estimate was conducted (Table 2 Appendix B) so to find likely position of centre of gravity (VCG) and to check max weight allowable for structure and equipment. Thanks to the drawings available to the author some useful parameters were found using “Barkla” scaling method (ref3) (Table 3 Appendix B).
• Wetted surface area (WSA)= 50,8 m2. • Prismatic coefficient (CP)= 0,5585. • Dellabough angle (Dell ang)=21,36º. • Area of the water plane=50,813 m2. • Canoe draft (TC) = 0,48 m.
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Chapter 2: Hull Design
Before going in to more sophisticated analysis it is worth to have a look in the latest development of oceanic racing yachts. Where it seems that two opposite philosophies are ruling the designs (ref4). On one side there is the “Van Peteghem” approach where the bet is to have a extremely light displacement hull characterized by almost vertical freeboard, with some sorts of chine as on motor boat, and a more forward distribution of volume to keep the bow up when planning and to avoid broaching. Relatively its designs have less sail area easier to handle end more reactive. On the other hand “Koujoumdjian” designs are wider, heavier with more ballast and there fore huge sail plans. More stable, theoretically require less sails changes end should be able to achieve higher maximum speeds. From the above some conclusions can be gathered for the project in discussion. In the opinion of the author the light displacement choice will perform better in buoys regattas been more reactive with higher acceleration while the more powerful seams more orientated on pure speed purposes. Keeping in mind that this work is a self-learning process and the lack of experience of the author. The design philosophy adopted here will be to process three different hulls trough “Max Surf” software following the two approaches listed above plus one that fall in the middle. Then it will be possible to analyze the different performance in different wind condition trough “VPP” software (ref5). The results were showing benefits for the lighter choice, but this was done with preliminary data. The author wanted to test this differences with more accurate in put but a major failure occurred on the lap top and the hard drive of the author and all the hulls developed trough max surf were lost. So due to time restriction a new hull was developed characterized by in between values.
Waterline length (LWL) has to be the maximum for the same displacement increasing length decrease resistance. Speed is proportional to resistance. The two main parameters effecting hull performances are LWL and displacement. On waterline breadth (BWL)
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some study will be done on increase resistance versus Power to carry sail. The volume distribution of the hull is characterised by several geometric
parameters. CP, LCB and LCF are the one frequently used in yacht design. These ratios have been subject of many researches, studying their influence on hull resistance. By the use of Delft series algorithms is possible to gather some useful conclusion, as it will be explained later.
2.1) Hull length
From the parametric study the wetted length of the hull ranged from 17.8 m to 18.8 m. This parameter will have effects on the up wind performance of the yacht as a longer hull operates at a lower Froude’s number experiencing a
reduction in the Total resistance (RT). A longer LWL will also results in a smaller angle of incidence of the water lines at the forward end. At this stage for common sense it will be kept as 18.3m.On the other hand It is believed that a more pronounced stem overhang will allow the yacht to increase in apparent waterline length as it heels while maintaining a minimum wetted surface (WSA) when upright. This aspect will produce benefits when sailing in light wind condition without compromise the performance when a bigger lifting surface is required.
2.2) Froude’s number evaluation
In order to make some resistance prediction using Gerritsma series (ref6), which
covers upright Frictional (RF) and residuary (RR) resistance, heel drag (RH) and
induced drag (RI); some estimation on which (FN) the yacht is likely to operate needs to be done. The Froude numbers of the design have been calculated and are summarized below: Tab 2.2
υ Froudenumber = g* LWL • @ 5 knots: FN = 0,192 • @ 10 knots: FN = 0,384 € • @ 15 knots: FN = 0,576 • @ 20 knots: FN = 0,768
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It is likely that the boat will sail most of the time in the 0,4 to 0,45 Froude number ranges. In order to obtain some reliable results some estimation of appendages dimension need to be evaluated. The tab 2.2 reports some dimensions based on percentage of sailing area as suggested on Larsson (ref7), the values are a bit low due to the high speed expected. Regarding the bulb dimension some estimate were done using “Max Surf” based on a weight of 6000 (kg) so to keep the ballast ratio to 54% the material used was lead as common practice suggested.
2.3) Waterline breadth investigation
This first analysis was done to have a general view of the problem, as beam effect many components making the analysis too complicated. The difficulty is that as beam increases hull area increases, righting moment (RM) increases, loads increases and for example mast weight increase. The length/ breadth ratio gives a relatively narrow hull and it was decided to push the waterline breadth as far as possible in order to get some form stability. A spreadsheet has been written to assess the effect of waterline length (BWL) on transverse meta centric height (Bmt), which is a key parameter for form stability (Table 4, Appendix B) and wetted surface area (WSA), which causes friction drag. This analysis shown that for a waterline breadth of 3,8 m, which is believed as the maximum achievable, the Bmt increases of 18% compared to the 3.5 m BWL case (suggested by parametric study), for an increase in WSA of only 7%. Therefore it is worth going for the largest BWL achievable as the impact on stability is decisive and the change in WSA is acceptable. Even if for this design a great amount of stability will be provided by the crew, in combination with canting keel, a large BWL will help to obtain a flat planning surface which will drive up down wind performances.
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Fig. 2.3 a: Four different hulls were processed through the Delft algorithms, designed to the same displacement with different waterline beam but same CP, LCB and LCF, from the previous spreadsheet it seams that the benefits will increase with breadth, and so the range tested was from 3.8m up to 4.6m. The results (figure 2.3a) are presented as percentage of increased resistance versus Froude number for different BWL, where the 0 line indicate a BWL of 4 m. Is possible to see the benefits of a narrower hull over the operational range of the yacht. This can be explained as an increase in WSA hence more friction drag (Rf).
This is true for the up right resistance (light wind condition), but it is believed that some extra WSA will come in handy in fast down wind runs providing more flat planning lifting surface. At this stage the BWL will be kept as 3,8 m. more studies on heel resistance with some more precise weight distribution will be done later on Using VPP evaluation.
An other aspect to consider is the fact that bulb weight is much more effective that on conventional keel configurations on producing Stability:
• Righting leaver on a Normal keel: = L *sin(θ)
• Righting leaver on Canting keel: € = L *sin(θ + φ)
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Where (Ø) is the angle of heel and (ø) the canting angle assumed as 40º, it can be seen that for 15º of heel the gains are about 38%. This means that the repartition between ballast stability versus form stability should be more orientated on the ballast one. This means that it would be possible to have a narrower hull for the same righting moment.
The VPP analysis was conducted to investigate the influence of beam on performances; from the previous it seams awarding to study the behavior of smaller breath. Again four boats were modeled varying BWL (range tested 3.5 m up to 3.8 m), sailing area and displacement allowing for
CP and LCB variation. Regarding the displacement the extra weight was divided proportionally in to bulb and structural weight. The gains in RM will effects the loads in the mast, which will eventually increase its section and the chain plate weight. But differences were too small to draw sensible conclusions, there fore those have been neglected. Up wind 5
0 0 5 10 15 20 -5 BWL = 3,6 m" -10 BWL = 3.7 m -15 BWL =3,8 m second /1mile -20
-25 TWS (knots)
(Fig. 2.3.b)
The results shown in figure 2.3.b are presented in TWS versus gains in seconds over a mile at a true wind angle of 36º (the 0 line here is the trial horse with BWL =3.5m). The graphs illustrate that above 10 knots of TWS the fastest boat is the largest one again. Significant loss are predicted below 8 knots, but in this condition the crew will rather use a Code 0 providing much more sailing area so again the best boat appear
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to be the 3,8 m one. The final BWL from “Max Surf” had a value of 3,74 m.
2.4) Mid ship section
The main choice when designing mid ship section is how much flair to have. A more pronounced flair would increase BOA and hence more righting moment produced by the crew and sails situated at the edge of the deck. The other side of the medal is that when the boat heels, the asymmetry of the waterlines will be more pronounced and there fore more heel drag will be produced. Hull weight will experience some changes as well.
The author wanted to test those effects on VPP modelling, but it seams that the prediction of heel drag is influenced by BOA/BWL and BWL/TC, which are up right parameters, and heeled wetted surface. So it is believed that the results will not be accurate enough to test flair influence on hull performance. A more visual method was used based on drawings available to the author. It also been seen that the IRC rule does not give handicap for flair as the measurement are based on BOA. From drawing 12 appendixes A is possible to see the water planes as the yacht heel at 5º, 10º, 15º respectively. It seams that the asymmetry of the waterlines will be less pronounced in between 10º and 15º this is believed to be the range in which the vessel will be sailing the most from initial VPP investigations.
2.5) Shear line and freeboard
The freeboard choice was driven by two major aspect minimum weight and headroom. The two concepts are conflicting each other. It is believed that inner headroom is not really an issue on a racing yacht like the one under study. It is also true that a higher freeboard will help the crew giving a more comfortable end dry area of operation. Considering
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that the vessel will be equipped with a canting keel device plus the wide beam, it is believed that some extra freeboard will be favourable. From the stile side of things a high shear line is not looking sexy. There fore some curvature will be applied. The design will have a concave shear line so to have more headroom in the middle for accommodation, other benefits are low weight at bow and stern (smaller gyradius) and better inertia to help structure sustain mast loads.
2.6) Bow shape
Nowadays racing yacht present very steep bow characterised by low flare. Benefits for the yacht under study are so to get increased LWL for a fixed LOA, to increase fineness of the waterlines in the fore part of the yacht as the angle formed by waterlines to the centreline (CL) decreases, effects are also expected on added resistance in waves. Dr Keuning has conducted studies on this behaviour on two models of a typical “Open 60”, showing that there aren’t large influences on the calm water resistance. “The fine waterline entry does not influence the added resistance due to waves to a large extent because the relative motions at the bow make the shape of the bow above the still waterline at least as important as the shape below it”. Significantly larger difference have been noted in head and in following waves, but “with respect to the safety of the yacht the increase of the relative motions at the bow may cause an increased probability of deck submergence” (ref8). In order to prevent this latest behaviour it was tried to increase the section draft at the bow so to have some more buoyancy in this region and increase further more the fineness of the waterlines.
2.7) Cp and LCB positioning
Sailing yacht CP are usually falling in the range of, .54< CP <. 58, with lower values resulting in finer extremities and higher values giving more
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blunt forms. The Delft series algorithms can be used to have an idea of 9 good CP and LCB (ref ). However these evaluations for optimum position are done varying one parameter only, but from common practice it is known that it would be almost impossible to change CP without effecting WSA or LCB. There fore results must be taken with care.
Fig. 2.7:
The graph in figure 2.7 shows percentage of increased total resistance
(RT) over a range of FN for a given CP. Results reflect the test conducted by the Delft unit. It is possible to note that for the likely operational range of Froude’s number defined before, the best CP would be .58.
From the theory it is known that at low FN were the viscous drag (Rv) is predominant, the adverse pressure gradient on the aft body should be minimized having a more forward LCB and lower CP. Otherwise at higher speed a blunter stern is favourable to delay separation and obtain a greater wave length. But considering the need to compromise between up to down wind performances it is believed that the handicap given by lower CP at high FN will be more penalising. The final CP from “Max Surf” was .56.
It is likely that the boat will sail most of the time in the 0.4-0.45 Froude number range; hence the LCB has been placed aft to put more volume in the aft part as shown by the section area curve (Fig 5, Appendix B).
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Furthermore this volume will be an advantage for downwind performances as it permits to have a wide waterline breadth in the aft part, which promotes planning. The LCB position from mid ships (percentage of waterline) is 6% aft.
A final discussion on CP and LCB position will be presented later in the stability chapter, where some studies on the effect of crew weight on underwater shape will be done.
All final Drawings are presented in appendix A.
Figure 2.8 shows an evaluation of total resistance vs. Boat speeds from the VPP.
Fig 2.8:
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Chapter 3: sail design
3.1) Configuration
In order to reach maximum performances the rig and sail plan needs to be as efficient as possible. On high performance sport boats as the latest generation of IRC and the new VOR 70 the usual configuration is a fractional rig, easier to trim and provide better performances than a sloop rig. Indeed such a configuration provides a better control of the main surface, as the top of the mast can be bended aft, having for consequence to open the leech of the sail and move the center of effort backwards. It also provides higher forestay tension, which is necessary for upwind performances. Therefore, it permits to sail in a wider wind range and the full sail area can be kept longer by adjusting its power (chamber, flatness). Furthermore the centre of pressure is lower on fractional rigs as consequence a smaller heeling moment will be produced. The disadvantages will be to have some more air drag due to 7 more stays used. Looking at IRC vessels a repartition of /8 is used as common practice. Some discussion can be made on the fact that this is 3 not the most efficient one (compared to /4), but it is believed that the boat will rate better under IRC.
From Larson (ref10) “ sails can be seen as foils, a sail has virtually no thickness, but it has chamber which is quite large”. Milgram stated that as for foils the most important efficiency parameter for sail is Aspect
Ratio (ARg) as (P/E; I/J). These are the geometric aspect ratios, some mirror effects from the water surface are expected and there fore they should be multiplied by a factor of about 2.
Marchaj (ref11) did several research at the department of Aeronautics and Astronautics at Southampton University on the effects of aspect ratio on performance. He tested in a wind tunnel different sail plan at different angle of attack. His results show that at close apparent angle (AWA 30º) the bigger the (AR) the better. But a reduction in Lift/Drag
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ratio is noted for larger angle (down wind). His work state that benefits are restricted to an (AR) up to 6, because with increasing aspect ratio the mast section needs to be increased producing a smaller average chord length of the main sail, and there fore some efficiency losses. His tests were conducted with aluminum mast, so it is believed that a carbon mast will have a thinner profile and therefore AR can be slightly increased.
3.2) Sails
Another very important aspect to consider in sail design is Induced drag
(Di). “This drag component is a measure of the wind energy inseparably expended in obtaining a lift force” (ref11). In other words, every lift- generating device spins airflow near its tip in to a kind of small tornado called “tip vortex”, or trailing vortex. The origin of this vortex is the flow moving from higher pressure to lower pressure side around the ends of the foil. So the difference in pressure (∆P) gets smaller and so do the lift towards the tips.
L2 Di = k • Formula 3.2: "Ar From formula 3.2 is possible to see that higher the aspect ratio the smaller the pressure lost (leak). This will actually suggest a more flat ! and shorter foot and head for the sails, there fore a square top main shape is going to be used by the main. This huge sail will be designed to provide a fair twist at the head so to prevent separation of flow due to a larger angle of attack (alpha) this will actually reduce the pressure loading and hence induced drag. Full battens will be used in order to better control the chord wise shape of the sail.
Regarding the jib an interesting area of study was the interaction of the two sails working together and influences due to the gap distance between the two. Bergstrom and Runzen studied this particular behavior of combined foils, showing some benefits in reducing the gap between them. As the air approaches the main sail at a smaller angle of attack
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(alpha) than if it works alone, while the opposite works for the jib, thus the main get unloaded while the jib gets more load.
For this particular case the jib would be relatively small compared to the main, having the sheet control point just in front of the shroud attachment to the deck, the trolley allows to move the leech transversely to ad more feedback on the rudder and better trim its shape. It is questionable if this small sail will provide enough driving force at slower wind speeds. It is believed that the use of a Code 0 armed at the end of the bow spirit will actually do. Providing a much larger sail area and a very flat and smooth surface characterized by a very high lift /drag ratio, optimum for this particular condition.
3.3) Sail inventory Sail Design is a very complex task. As it needs to take in to account wind speeds and angles as well as see state. Obviously all the previous are unknown, as the yacht has to perform as an all rounder but hopefully sailors will be able to trim the sails properly so to match with the required weather condition. Usually the approach is a compromise between points of view from sailors, sail makers and aerodynamicist.
Tab 5: Sail inventory
The designs involve CFD studying sails as 3-D foils, and wind tunnel test so to obtain force coefficients. These methods are very expensive and 28 CORTO MALTESE 65
time consuming and obviously not available to the author. The VPP sail coefficient library will be rather used this will lead to some precision losses, especially in the Code 0 case. In Tab 5 is possible to see a typical sail inventory for this type of yacht, this is been developed using VPP but as to be considered as a preliminary set as a proper one will be designed by some sail makers not yet specified at this stage of the project (most probably “North- Sail” or “Quantum”).
3.4) Balance
The CE was estimated to be around 12 m. Due to the position of the dagger boards the CLR will be more forward compared to more traditional configuration. The crew will therefore need to trim the mast properly to achieve balance that will be an easier operation tanks to the fractional rig yacht that has generally less lead compared to a mast head rig. Comparisons with other modern racing yachts or even racing dinghies has shown, that for boats with high RM the lead is generally in the region of close to zero. An explanation for this is that these boats sail with generally less heeling angle and due to their increased speeds with small angles of attack. In consequence the offset of the CE of the sails from centre plane is small compared to large heel angles creating a smaller yawing moment to windward. Also the centre of pressure on the foils is moving less due to high aspect ratios and small angles of attack. The proposed boat is equipped with dagger boards and rudders angled to design heel angle of 15˚, and will pose no negative effect on the balance for the above-mentioned reasons.
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Chapter 4: appendages design
The main task for the appendages is to provide enough Lift (L) to overcome the sails side force (SF), and give the yacht the ability to keep a straight course, on more common designs the procedure is to find the optimum balance between hydrodynamics requirement and structural loading especially for the keel been the most important on this respect. The large weight of the bulb at the end of the keel has to keep the boat up right and stable, the length and shape play a decisive roll here. The keel fin, the link between the bulb and the hull, contributes greatly to optimizing the hydrodynamic behavior of the yacht. This is the heavily loaded component. There are various design criteria to consider. First off all the hydrodynamic aspects, that is to say the fin must cut through the water, with very little resistance. That means to be very thin, on the other hand a certain thickness is needed to take forces and bending moments that acts on it. For example when the boat is tacked, the lateral acceleration act directly on the fin in the form of a bending moment, it has to be able to absorb this loads making its design a real engineering challenge.
To makes things even more complicated a canting keel device is going to be used, this means that as the keel is canting up to 40º is projected area required for lift (L) production will be reduced. There fore there will be the necessity to have some other sorts of lifting surface like a dagger boards. Looking at oceanic racing yacht it seams rewarding to have two separate retracting foils positioned some distance from the longitudinal centre line of the yacht (CL) than a single centerboard. There are some benefits in do so as it will then be possible to adopt an angle to the surface so to maximize the draft (Tk) when the vessel heels. In deed the study and optimization of such appendages configuration is a very complex task. It needs towing tank test data, wind tunnel test and CFD. All the above are time and economically expensive and not available to the Author. So the approach used will be based on data coming from literature available on the subject (ref12) and the extensive
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studies conducted on “NACA” section some fifties years ago by Abbot & Von Doenhoff (ref13). Where the main parameter affecting the hydrodynamic behavior are:
• Aspect ratio: From a plan form point of view is the main parameter defining the Lift (L) over Drag (D) ratio, the slope of
L/D curve increase with Ae and hence the efficiency. It also
influences the stall angle. For yacht application the range of Ae are above a value of 4. Formulas 1; 2; 3; 4;(Ref14 ) • Thickness / chord ratio: Observing the flow of water pass a foil, then the ideal case would be undisturbed stream line flow, the thinner the fin the nearer to this ideal behavior. This effect is very small on the lift curve slope, as it will slightly decrease the
section pressure form drag (Cd0). On the other hand a reduction in t/c will lower the angle of stall, so the previous benefit will be lost at higher angle of attack. • Frictional effects Reynolds number dependency: Lift generation comes from difference in pressure gradient along the chord. As (RN) increase the boundary layer will develop some transitional or even turbulent behavior effecting the Pressure distribution and hence additional drag is formed. At small angle of attack there are some benefits in trying to have a laminar flow over a larger portion of the chord.
• Angle of attack.
The effects of sweepback angle or taper ratio are in the order of 0,04 % so considered in effective for this study. From VPP output for Aerodynamic forces for different wind conditions (TWS, AWA) is possible to derive the side force (SF) the foils needs to produce to maintain the yacht on sailing equilibrium. Tab 6 shows the main dimension tested.
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Tab 6: Lift subdivision of lift
Item % tot lift wsa m^2 span m mean c m t/c
Keel 0% 5,28 4,4 0,6 12
Dagger board 80% 2,18 3,2 0,43 12
Hull 5% n/a n/a n/a n/a
Rudders 15% 2,4 1,8 0.4 12
Bulb n/a 4,49 n/a n/a n/a
4.1) Canting keel fin
For this particular case it is believed that most of the lift will be produce by the other foils (worst case scenario will be 0% and therefore this assumption will be used). So in the design of this surface the emphasis will be on the minimum drag achievable for a required thickness (governed by structural requirements). Further more, when the keel is canted the angle of attack will tend to zero. From figure 6 appendix B is then possible to see the benefits of using a 65 series NACA section with a T/C ratio of 12% as it will produce a smaller drag for a given lift coefficient. Is arguable that in light wind condition when much more less RM is needed the keel being less canted will produce some lift and consequently drag but this aspect can not be analyzed without proper tank tests. Regarding the dimensions tab 6 the maximum draft was taken from the VOR 70 rules as 4,8m so to get the maximum righting moment, the chord was restricted by the t/c ratio for the section selected.
The stability effect of this device will be explained later in the chapter 7.
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Typical DB and CK installation from open 60: 4.2) Canards
The use of this additional lifting device has the downside effect of increasing the wetted surface area (WSA) of the yacht, but on the other hand tanks to its retracting ability, the crew will have the possibility to trim the amount of surface used. There fore some benefits are achievable, when less lift is required (downwind or in light airs) it will then be possible to reduce the frictional drag (RF), which is highly dependent on WSA.
The aspects to consider in the design procedure of this particular foil are the following:
• This will be the main lift generating device • The hydrodynamic behavior is similar to a normal keel (operates at low angle of attack (alpha)) • Not heavily loaded (no ballast) smaller section can be used (t is deflection limited). • Set to an angle of (ø) so to improve the maximum draft achievable at 15º of heel (Ø), positioned at an off set distance from yacht centre line (0.95m) so to be more in line with the rudders, and reduce transverse leaver from CLR to CE. • A sweep back angle can be applied so to do not shift CLR to much forward
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From the above from a the section point of view is possible to see benefits in NACA 63 12% (Figure 6 appendix B from Abbot) from tab 7 Appendix B the minimum thickness required was around 8 cm so to maintain a 12% distribution the chord needs to be of 0,65 m giving a mean chord of 44 cm. From simplified formulas from “lifting line theory” (ref15) Knowing the coefficient of lift required (CL) from VPP (Tab 8
Appendix B), setting an alpha of 3,5 degrees, and assuming a CL 2d of about 0.1 as suggested on “Larson (ref15), then from formula 4.2a,b,c is possible to find the span required.
(b) C (a) s C = L 2D •α AR 1.9* L 2 e = 1+ c ARe s € € 2 € € ARe = C •α (c) L 2d −1 CL Giving a span (s) of around 3,12m. €
€ The effect of downwash (w) can be seen to reduce the apparent alpha (lost of lift) but was neglected here, as needs CFD analysis.
It was then tried to modified the span by 20 cm on the VPP (Fig 4,1 Appendix B) so to notice (if any) the difference in VMG output but the effect were really small (less than 0,02 of a knot) for slower speed but is possible to see some benefits at higher speeds with a span of 3,0 m compared with the 3,2m and 3,4 ones. But it’s believed that those results are not really reliable so the span will be kept as 3.2m.
4.3) Rudders
Nowadays seams to be common practice for ocean racers to have a twin rudders configuration. For this particular design as for the dagger boards they are angled at 15 º to the centre plane, so to achieve the maximum draft in sailing condition (more or less the same angle of heel (Ø) from 34 CORTO MALTESE 65
VPP results). Positioned to port and starboard at an offset distance of 0,95 m, it seams awarding to do so as they appear to be more centred to the underwater plane at 15º of heel (Ø). The hydrodynamic benefits of such a configuration are well known and can be briefly explained as by reducing the lift (L) on each one of the surfaces, keeping the span unchanged, the sums of induced drag (DI) become smaller than for one 15 surface alone. From “lifting line theory” (ref ) (DI) is proportional to lift squared, assuming no interference, halving the surface the resistance will drop to a fourth of the original. In other words the (DI) will be half. Further more the offset distance from the centre line will help increase the balance of the yacht as the CLR and CE will be more aligned. On the down side there will be an increase in wetted area and hence frictional drag (RF).
Rudders may be similar in shape to normal keels but it has various different functions:
• A) To provide maneuverability, hence yawing moment which consequently will cause the yacht to turn. • B) To provide side force (SF), and resist to leeway. • C) Directional stability (down wind).
Another aspect to consider is the fact that this surface will operate at much large angles of attack (å). There fore the benefits of a drag bucket seen for the 6 digit series disappear. Four digit series characteristics seam to cope better with the requirement as present much higher stall angle.
Again optimization was not possible without CFD analysis, but useful conclusion can be gained from Molland work (ref14). His research provide design procedures for rudders of high performance yachts, employing free-stream data together with the relevant corrections for effective aspect ratio, inflow angle of attack and velocity.
All the formulas used in his study are presented in (ref14).
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From those is possible to see that the lift curve slope has a non-linear behaviour and lift is composed by:
1. From flow in the longitudinal plane. 2. From cross flow
While Drag is composed by:
3. Friction and form (Cdo).
4. Production of lift (induced Di) proportional to Ae.
ref14 1) Is mainly influenced by Ae as from formulae in note that there will be some losses as there will be a boundary layer present over the adjacent flat plate (Hull).
2) Not really effective and dependent on thickness – chord ratio.
So sails forces have been evaluated trough the VPP analysis and then used to evaluate the bending and torsion moment acting on the blade in accordance with the ISO 12215-8 rule for stock sizing presented in appendix C). Once an allowable stock was achieved and allowing for a laminate thickness…. That means that the t/c need to be of 12% so c and
Ae was found and consequently span around 1.9 m.
Some checks were done to see the angle of attack needed for the rudder to produce enough lift. It was noted that the worst case condition was occurring around 60º of AWA so for the purpose of the project the minimum span calculation were base on this lift requirement (the same was done for the dagger board) results are presented in tab 8 Appendix B. Another study was conducted to see what leeway angle the yacht will be likely to assume after a tack assuming a speed of around 6 knots. If the boat had to tack from 90º to 90º then the leeway needed to balance the sail force will be huge around 22º (the repartition of lift was varied for this case allowing the rudder to produce more around 35% of the total). This value is very high but it is believed that rarely the yacht will experience this type of turns.
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The effects of the windward rudder coming out of the water was some how neglected here. The study was conducted as the submerged rudder was working alone in the production of lift. Tanks to Hydro Max it was all do possible to notice at which heel angle the rudder will start to ventilate. It was possible then to input this value in to the VPP but it is not known by the author how the software treats this data, so more studies should be carried out in future work.
Chapter 5: structure
Introduction The discipline of structural design cannot be straightforward process, with clear input and readily available and usable output values. The structure it self may be complex and a variety of loads case have to be considered. The accuracy of those components determine the accuracy of final scantling:
LOADS RESPONSE
GEOMETRY STRENGHT ANALYSIS
ALLOWABLES (stresses, strains,deflections) MATERIAL STIFFNESS
The method used is frame spacing orientated and consider longitudinal primary and secondary stiffeners as well as the transverse framing and bulkhead as single unit not as a complete unique structure acting together to sustain the loads, so stresses (σ) and shear (τ) should be
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more accurate. Hull shell and deck plating structure was based on traditional plating theory, further more investigations on high deflection theory may be needed.
The evaluation of load was based on hydrostatic pressure, therefore further more analysis should be made in order to investigate the impact of slamming areas on the structure, as well as the critical stresses from the mast must be identified in all relevant direction and be compared with allowable (buckling and stress check for deflection).
The boat is going to be constructed in sandwich with carbon skins and Nomex core.
The best solution for a light structure is to opt for a sandwich construction, which will also reduces the building time. Indeed sandwich structures panels are much stiffer than single skin panels and consequently are able to carry much greater spans without too much deflection, which means that a limited amount of stiffeners and clothe layers are required, cutting down the costs and time. In order to maximize the benefits of this type of construction the vessel is going to be transversally framed as “Nomex” allow for large panels.
Typical Carbons skins and Nomex core sandwich construction:
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Materials
The following directive needs to be followed in order to rate under IRC from ORC rules: 101.2 The following materials are prohibited: a) In hull and deck structures and rudders: High Strength (HS) carbon fiber with modulus exceeding 250GPa. b) In spars with the exception of booms: Cored sandwich construction where the core thickness at any section exceeds the thickness of the two skins. c) Any metal alloys containing titanium with the exception of generally available production hardware items. Titanium is not permitted in lifeline elements (stanchions, pulpits, pushpits etc.)
d) No material with density greater than 11340 kg/m3.
e) Pressure applied in the manufacture of hull and deck structures greater than 1 atmosphere
f) Temperature applied in the manufacture of hull and deck structures greater than 80°C.
g) Aluminum honeycomb cores in hull shell and deck shell structures.
h) In hull and deck structures: Plastic foam core of nominal density less than 70kg/m3.
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5.1) Hull
5.1.a) panels
The ISO rule do not require for water tide compartments, but for safety reasons the ABS Offshore racing yacht directive was followed. There fore two water tide bulkhead have been placed at some distance from the forward and aft perpendicular respectively. The canting keel device manufacturer strictly recommends that two additional water tide bulkheads to be placed to enfold the canting box, so to assure that in case of failure the boat do not sink, and for a better distribution of the loads in to the hull structure. Other six structural bulkheads were placed so to divide as evenly as possible the yacht, and to reduce to a minimum the span of the panels. An additional BH was placed on frame I so to avoid problems if major failure occur to the rudder stock bearings. The bulkheads are in sandwich construction as well. The laminate properties have been designed as if they were all water tide with a water head pressure of 0.5 m above the highest point from base line. With this assumption is then possible to apply some large cut out to the structural one, considering that they have been design as a worst case scenario and there fore in reality the loads will be much more smaller.
Now that the vessel is been divided transversely is possible to study the panels and longitudinal stiffeners properties.
Some research was conducted to find typical panels areal density, a really useful source of information was the VOR 70 rule that state a minimum weight for panels in different region of he vessel ranging from 8 to 11 kg/m^2.
Using the Hull Scant software five different laminate have been created to mach the VOR areal density. Those are to be used in bottom, chine, side end deck respectively plus an additional reinforced one for the deck in the way of chain plates or sheet control points where Nomex is not recommended so a core-cell PCV foam will be utilized (materials
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properties are presented in tab 9 &10 Appendix B). Once the laminate were achieved was then possible to study the maximum short dimension spacing achievable. Then reading the requirement output from HS it was possible to identify the most heavily loaded panel for every region. The laminates lay up have been modified again so meet the minimum compliance factors (set as 1.05) for the worst case. Then the laminate was kept the same for every region respectively. It was tried to modify the core thickness rather than the skin lay-up so to facilitate the construction.
5.1.b) Longitudinal stiffeners
As internal volume is really not an issue on this type of yacht it was tried to gain mechanical properties from the geometry of the stiffeners rather than from their lay-up. Also to avoid excessive use of UD on the crown laminate so to keep the NA more centred.
A Cl girder will be fitted from frame E to the bow to help keep spacing on bottom panel down as well as provide some longitudinal stiffness. The forestay will be attached to it and the mast foot will be placed on it. The pivot of the canting keel will be supported by it.
Two side girders will be placed on the chine at a distance of 1 m from the centre line to support the keel box and transmits its load to the hull structure they will run from frame B trough F They will also provide the major support for the dagger boards box.
A pair of stiffeners was used to reduce the panel dimensions on the side and hopefully provide some extra strength in case of collision with other vessel (in buoy regattas); they will run from frame B trough F.
Forward than frame b the panel dimension reduce considerably due to the yacht shape so just 2 stiffeners will be used in this region.
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In the aft region of the boat two transverse structural BH were used to enclose the engine room running from frame E to the aft end to support the cockpit. They have been considered as longitudinal stiffeners as it is been seen on modern race structure. But analyze this component on hull scant was impossible due to the web likely shear failure. As the aft sections of the yacht are quite large other two stiffeners will be used from frame e aft.
Deck is mainly sustained by the structural bulked, A pair of girders will also be used to support the deck panels, in Order to reduce panel spacing and give more support for the stresses coming from sheeting control points as well as from the winches.
Some reinforced panel are going to be used on areas in the way of chain plates and sheets control points. For areas were screws needed to be fitted a different core material was used PVC.
5.1.c) Conclusions
Optimization of the structure to reduce weight and lower centre of gravity was not really achievable with the tool used. The structure was assed to meet the compliance factors. Mainly to check that the structural weight allowable was in the range of the estimation and to have a more accurate weight estimation critical for the preliminary stage Appendix C tab 2. The overall weight was around 2300 kg well below the one predicted in the parametric study. It is believed that an accurate analysis using FEA will probably allow to improve even more. All the above should be read in reference to Drawing 3 and 4 Appendix A and the out put from Hull Scant are presented in tab 1 appendix C.
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5.2) Appendages 5.1.a) Cariboni keel experience
For the fin diverse type of material choice were available, tab 11 present the pro e cons it seam that major failure have been occurring due to fatigue in this respect a milled steal seamed more appropriate.
KEEL FIN TYPE: Material Carbon Fabricated steel Milled steel Typical 450 kg 650 kg 1.100 kg weight Typical max 120 mm 115mm 100mm width Pros Light weight Lighter than milled Thin section Heavier bulb steel Less drag Fit and forget Lees Better upwind radical/expensive performance than carbon Durable Cheapest material Cons Flutter Finite life- periodic Manufacturing problems replacement lead time Expensive Regular Expensive Poor impact maintenance Poss. voids in resistance required casting Damage can Possible Heavy. be invisible manufacturing More wetted flaws surface Weld failure. Tab 11:
Using a simple beam theory approach a minimum thickness (t) was found. Assuming the keel to act as canting leaver under a point load (Bulb weight). The deflection Max was limited to 2 cm, then rearrange the formula is possible to find (t) around 10 cm. With a FoS of 2 but if Weldox is going to be used FoS may be increased. Further consideration may need to be applied for design of the keel head to take up the loads from the hydraulic rams. In order to design this with minimum weight penalty, a deeper analysis using FEA is recommended, and obviously beyond the scope of the project. The canting system is been intensively studied and analyzed by the manufacturer (Cariboni Ref22) using FEA. They assure that their A frame
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structure will sustain all the loads coming from the rams and transmit just the righting moment to the hull.
5.2.b) Rudder and Dagger boards
The two wings are going to be built in carbon pre-pregs laminates. A similar approach was used limiting the deflection to 2 cm and evaluating a minimum thickness (t) of 8 cm with a FoS of about 2 so to allow the blades to fail before causing major damage to the hull shell. (Tab 7 appendix B).
5.3) Mast & rigging
The loads acting on the shrouds and stays have been estimated using
Framework theory and the minimum required breaking strengths have been calculated using a factor of safety varying along the height of the mast so to avoid major failure in the lowers panels. In the opinion of the author is been considered to be rewarding to do so as is preferable to lose the top of the mast as it will still be possible to use the sail and there fore allow the crew to sail to the closest safe harbor. The materials used in the shrouds are going to be manufactured by Navitec (ref17). Using a double braid with “Zylon (PBO with polyurethane coating” core and “Dyneema” Cover Properties in appendix C allowing for considerable weight saving if compared with “navitronic 50” around 10 times lighter. The final product is going to be colored in black as the mast so to provide a much more sexy and aggressive looking.
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The properties and specifications are summarized in the table below:
Tab 5.3:
The mast section selection is based on the total mast compression in the lower panel which has been calculated using framework theory (ref18) assuming the following:
• The Jib force to act as a point load at his head. • The main force to act as a uniform distributed load. • The worst loads the mast will encounter in its life are in a knock down situation, therefore the mast have been analyzed under the same load as the righting moment at 30º of heel.
Then the minimum required section has been found using Euler theory on struts: nπ 2 EI PCR = 2 L
A factor of safety of 3 has been used to calculate the minimum section. € Minimum required transverse Flexural modulus (EI) was found and then looking at various manufacturers (ALL Spar) it was possible to select a proper section Appendix C (MAST SELECTION). To avoid deck failure a ring is going to be fitted around the mast section and fixes trough A- frames to the aft and fore bulkhead in this region.
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Chapter 6: General arrangement
6.1) Interiors
The interiors have been tried to be designed in order to keep the weight to a minimum and keep the centre of gravity as low as possible, as well as concentrate the weight “ It should be remembered that that heavy weights far from The total centre of gravity increases the gyradius, and have negative effect on the performance of the yacht in a see way”.
Comfort was not an issue on this kind of yacht. A total of 12 berths were fitted, as this is the minimum required crew number for sail the vessel at its maximum performance. They consist in 12 bench designed to be set to different angles to the transverse plane of the boat so to assure comfort to the crew when the sailing at high heel angles.
Particular effort was put in to the design of the chart table so to assure space and comfort to the navigator when sailing in rough seas.
The vessel was equipped with a Cooking station with a gas tank of 15 litres and a WC essential for long off shore races.
The aft region of the vessel is going to be used for storage of equipment, while the front is going to be used for the sail storage.
The yacht is going to be equipped with 3 exits. One in the bow to make easier the movements of the huge sails to the deck. A main entrance at the end of the coach roof. And an emergency one at the end of the cockpit were the Life raft are going to placed so to assure a fast and safe operation if the vessel needs to be abandoned at sea.
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6.2) Machinery and tanks
In order to save weight the electrical supply is going to assured by the engine avoiding the use of a generator, which is quite heavy. The engine chosen was the Volvo Penta D2-75 hp which is quite big for the vessel but its believed that customizing the alternator it would then be possible to assure all the electric power required (Specs for the engine are in the appendix D). The engine is going to be equipped with 2 Batteries of 90 ampere each.
In designing the tanks an effort was put in to try to lower their centre of gravity to the minimum achievable. In order to do so they are quite long and have short vertical dimension. A total of two tank of 50l each for the diesel positioned close to the engine to reduce the amount of pipes running trough the yacht. Positioned symmetrically to port and starboard respectively.
The same philosophy was adopted for the fresh water tanks with a load of 100 litres each. On long off shore races the water is going to be provided by a water maker placed in the aft region of the vessel, so to avoid excessive weight.
6.3) Deck
All the instruments are going to R&B and the position will have to be finalized with the crew.
The deck was design clean and flush so to provide easy manoeuvre for tacks and jibes. All the deck gear will be manufactured by “Harken” and finalization of the position of winches and sheet control point needs to be done with crew, manufacturer and sail makers.
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All the above should be read in reference to appendix A Drawing 5 appendix A
Chapter 7 Stability
At a preliminary stage a first shoot evaluation of the “STIX” value according RCD practice code was done tanks to a spreadsheet provided by lecturer (ref 19) Appendix D tab 7. To check that the vessel was falling in “Category A”. As it is possible to see from tab 8.1 appendix D the “STIX” is well above the minimum achievable.
Once the hull parameters were defined, then the yacht was modelled in MaxSurf and imported in to HydroMax where the stability analysis was carried out in. A spreadsheet for the weight estimate was carried out since the early stage of the project. Is then possible to include the final weights and centre for the different areas as Interior, Structure, crew appendages (canting keel and ballast), deck and mast. Fig 8.2 reassume the major item considered ( the full weight estimate is presented in the appendix D Tab .1).
Fig 8.2:
The canting keel device shifting provides a large improvement of the stability the large ballast bulb will increase the RM considerably. On a racing yacht like the one under study some extra RM will be provided by the crew sit on the shear line when sailing.
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In order to represent this behaviour Four Different load cases have been developed so to consider the different sailing condition as light wind condition to heavy. Varying the longitudinal position of the crew and various canting angle. Final displacement was 13250 kg.
The stability was assessed in compliance with the ISO directive for mono hull sailing yachts; the report showing that the criteria analyzed were passed is presented in the appendix D Tab 8.2. The graphs in Fig 8.3 show righting arm (GZ) plot for different conditions.
Stability GZ curve
3,5 3 2,5 2 1,5 1 0,5 0 -0,5
GZ (m) 0 15 30 45 60 75 90 105 120 135 150 165 180 195 -1 -1,5 -2 -2,5 Heel angles Sailing trim Worst case scenario Keel on CL Fig 8.3:
Is possible to see the large benefits provided by the keel when canted at 40º. The Angle of vanishing stability (AVS) is always well above 120º as expected as a canting keel boat is usually pretty stiff.
No rules are provided for canting keel device so the VOR 70 and the ORC rules have been taken in consideration:
Volvo 70 Rules require: 1. A maximum keel cant angle of 40º relative to the hull
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2. Minimum AVS with the keel fully canted of 115º. This will equate to AVS with the keel on the centre line of c 135º to 140º.
3. A minimum empty boat weight of 12500 kg and minimum bulb weight of 4000 kg. From the graph 8.3 is possible to see that the yacht complies with the rule (Point 3 not considered). ORC rating system require:
Limit of positive stability (LPS) as calculated by the LPP from the measured righting moment shall not be less than 103.0 degrees, except for the Sportboats for which the limit is 90.0 degrees.
The stability index for offshore race category 0 shall not be less than 120 and shall be calculated as follow:
Stability Index = LPS + Capsize increment (CI) + Size increment (SI) (Ref20)
For a boat with water ballast or canting keel, the Ballast Leeward Recovery (BLR) Index represents such a boat’s relative ability to recover from a knock down with sails aback, i.e., knocked down with all water ballast or canting keel to leeward. BLR Index shall be calculated as 20 RA90• DSPS follows (Ref ): BLRIndex = + 0.5 6• SA •CE
Minimum BLR index = 0.90+0.007*(LSM1-5) = 0.9938 € From the above is possible to see that the vessel meet the requirements as Stability index exceeds a value of 120, and the BLR has a value of 1,786 so the yacht is in the range required. It was interesting to see how the LCB was shifting as the crew weight was moved longitudinally in combination with different cp the hull assumes. Tab 8.4:
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Tab 8.4 summarize those behaviour, where is possible to see that moving the crew the under water shapes of the hull can be modified, so to optimize its characteristics according the Froude’s number (FN) the yacht will operate at.
In order to obtain an even better hull forms at higher speeds an additional water ballast (1 ton.) was added so to help the boat to start planning providing some trim angle and avoiding the chances of bow submersion. Positioned aft of Frame I in order to maximize the leaver (Heavy down in Tab 8.4)
Chapter 8 Balance
Balance on this vessel was difficult to asses as the dagger board will shift CLR forward and was difficult to find reliable leed values for this type of yacht in common yachting literature. However it is believed that the area of the two rudders will help to compensate the CLR shift. Optimization is possible with mast trim and dagger boards sweep back so to achieve a more balance yacht depending on the wind condition an angle. From the VPP analysis it appears that the yacht is quite stiff as expected fro a canting keel configuration. So the lead required for balance will be lower than on conventional vessel. A spreadsheet was written, based on projected area of the foils, to achieve a likely CLR position presented in tab 8.1 appendix-D. The final position of CLR was estimated around 10 m from the aft perpendicular. The CE was assumed to act at a third of the chord and the span respectively, estimated as 10 m from aft perpendicular giving a lead of 0%.
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Chapter 9: VPP analysis
The VPP software revealed its self to be a quite powerful tool in defining hull parameters at the early stage s of the project, as explained in chapter 2. As well as in defining the sail side force SF and consequently the lift generation required by the foil to keep the yacht in sailing equilibrium.
A final vpp analysis was conducted so to predict the likely performance of the yacht. The four different load cases studied in Hydro Max where modeled trough LPP so to se the performance benefits provided by the crew movements on the yacht. The sail inventory was tested in different wind strengths and angles. Boat ratings are calculated from the predicted boat speeds, calculated for 7 different true wind speeds (6-8- 10-12-14-16�20 knots) and 8 true wind angles (52°-60°-75°-90°-110°- 120°-135°-150°), plus the 2 optimum �VMG (Velocity Made Good) angles: beating (TWA=0°) and running (TWA=180°), so it seam rewarding to test the same conditions.
Regarding the velocity prediction it has to be remembered that some inaccuracies are expected as the real sails and yacht coefficients can be only be defined by towing tank test in combination with some wind tunnel test and the air drag was estimated by the software. But its believed that for the up wind case and the lower down winds ones the out put can be taken as a close enough approximations.
Regarding down wind above 20 knots, as boat speed exceed a (FN) value of 0.6 it is believed that prediction are not reliable. The software assumes a linear increment in total resistance, which is not true as the yacht start to experience planning behavior. There fore it was not possible to test the benefits of the water ballast. This will actually be a very interesting subject to test in a towing tank so to study the effect on total resistance (RT) and the effect of trim so to help the vessel to enter in its planning behavior, at high speeds.
52 CORTO MALTESE 65
The results are summarized below in tab 9.1:
CORTO MALTESE
Best Boat speeds (kt)
TWS (kt) 6 8 10 12 14 16 20 25
TWAº
36 7,05 8,8 10,06 10,91 11,51 11,92 12,57 12,7
52 8,96 10,55 11,89 12,86 13,59 14,33 15,77 16,84
60 9,42 11,05 12,53 13,76 14,67 15,68 17,27 17,52
75 9,88 11,62 13,34 16,39 17,31 18,24 25,66 25,12
90 9,84 11,62 13,16 16,08 18,19 16,5 18,8 21,39
110 9,86 11,71 13,43 14,8 16,27 20,54 23,22 24,05
120 9,6 11,28 12,96 15 16,51 18,05 21,09 24,89
135 8,55 10,18 11,46 12,84 14,86 17,52 21,33 25,91
150 6,48 8,27 9,71 10,75 11,85 13,07 16,54 22,24
Up.Vmgkn 5,92 7,22 8,13 8,83 9,31 6,86 10,19 11,95
Dn.Vmgkn 6,09 7,46 8,44 9,36 10,49 12,39 16,15 20,46
Heelº 2,24 2,67 3,74 8,04 9,81 13,32 13,81 14,56
leewayº 2,74 3,51 4,03 4,09 3,83 1,9 3,23 2,82
Tab 9.1: Is possible to see that the boat do not heel that much as predicted and this will give some benefits in keeping the keel under water so less interference with the wave pattern and hence less resistance. The leeway angles are more or less in the range expected for a Dagger boards configuration. Regarding the speeds is possible to see that they are always above the wind strength (In light airs condition) this means that the yacht will operate more dependently to the apparent wind strength and angle. As it was said before the results above a FN of about 0.6 (15,68 knots) are not accurate enough to make sensible conclusions.
53 CORTO MALTESE 65
It would be interesting to make some prediction with the ORC VPP so to get an accurate value of the GPH the vessel will have while racing. This was not possible as the program is very expensive (around 500 quid). Some estimate have been done looking at similar boat and their GPH, but the results were not that good as the IRC rating rule is kept secret.
However is possible to predict that the vessel will probably rate under IRC Category 1 and the GPH is likely to fall in the range of 1.55 1.58.
The final polar plot achieved with the software is presented below in figure 9.2
Figure 9.2:
54 CORTO MALTESE 65
Chapter 10) Schedule
The student guide was pointing out an amount of hours about 350, It is true that the author did not keep an accurate schedule of the time during the development of the project but the total amount of hours clearly exceed this amount. The pie diagram below summarizes the time management along the design process (Tab 10.a). The above actually consider only the amount of work done in front of the computer and the time spent in research of reliable sources.
Time menagement Weiht estimate 14% Structure Research design Research CAD 11% VPP 16% 13% CAD Hull Design 23% Appendeges
Hull Design Mast design Mast design 14% Structure design 3% VPP Appendeges Weiht estimate 6%
Tab 10.a:
55 CORTO MALTESE 65
Conclusions
Is possible to see that the Design can still be considered at his preliminary stage, as more studies and research need to be done for finalisation. In the above report it was tried to understand and identify the major areas involved in the design of an aggressively orientated IRC yacht. The common practice method of the spiral is been followed and the Principles of yacht design learned during the three years of Bachelor degree in “Yacht and Power craft Design” have been put to practice.
The hull forms have been developed in accordance with the requirement defined in the design brief and the parameters can be considered more or less final, some refinement can still be done but it is necessary to conduct a towing tank test (e.g. studying the effects of longitudinal water ballast and test the hull behaviour at high speeds).
To improve the power to carry sails a relative beamier hull was chosen for gain form stability as it was seen that the increase in Bmt is more effective than the increase in WSA. A canting keel device will be used to increase the righting moment and therefore improve even more this aspect. The appendages were studied as 2-D foils and as if they were operating alone. More intensive studies will be needed here (the use of cambered foil for the dagger boards will have some benefits), involving wind tunnel test in combination with CFD analysis. But the improvements will be restricted to 4 to 6% of overall performances and therefore will not have a huge impact on the project. The structure was analyzed with simple beam theory and mainly done to check the RCD ISO requirements.
A lot of improvements can be gained here by the use of FEA tools in terms of concentration, weight saving and centres. But this will require the advice of technical experts as “High Modulus”. Structural consideration on the canting keel device have been purely based on the information provided by the manufacturer, but usually this kind of installation are almost totally customized. This two later aspect can have a major impact on the overall project, as they will considerably effects the weight estimate. Which as proven to be the more critical 56 CORTO MALTESE 65
process at this stage, as a lot of work can be done in optimizing the hull and appendages forms, but errors in the centre of gravity evaluation can lead in considerable lost of performance. As benefits of a particular hull shape will be completely lost if the yacht do not float on the decided DWL. Regarding the rating rule IRC the ORC directives has been followed and the yacht will be able to enter all the races it was designed for. A deep understanding of the rating handicap was not possible, as the rule is strictly kept secret. And the VPP software used to evaluate the GPH quite expensive. But as it was pointed on the design brief the emphasis of the project was performance driven. As in the opinion of the author is much more fun and challenging to win races in real time, sailing the fastest boat rather then get stuck in to the fleet hoping for the GPH to compensate the time losses.
57 CORTO MALTESE 65
References
REF1: Regarding the IRC Yacht the most successful designers were taken in consideration as Farr Bruce, Paperini Giorgio, Vismara, Felci, Ceccarelli, Frers, and Mills.
REF2: Regarding More oceanic orientated yacht, designers taken in consideration are: Reichel&Pug, Juan Kouyoumdjian, Botin-Karkeek, Farr, Humprey, Vplp, Verdier Guillaume, Sanderson Mike.
REF3 Allometric series from Barkla of University of St Andrews, Scotland; “Principles of Yacht Design (Larsson) chapter 2 preliminary consideration pg 12 Fig 2.1: Proportions versus size (Barkla).
REF4 “Fare vela” December 2008: “leggerezza contro Potenza” pg. 62.
REF5 Software used is from Formsys software and Wolfson unit software packages. REF6 “Professor J. Gerritsma started in 1974 extensive series of test with models of sailing yachts at the Delft University of technology”. From Principles of Yacht Design (Larsson) chapter 5 hull design pg 75. REF7 “Principles of Yacht Design (Larsson) chapter 6: keel and rudder design pg 140.
REF8 The international HISWA symposium on yacht design and Yacht construction, “The influence of the bow shape on the performance of sailing yacht” by Dr ir J A Keuning, R Onnink, A Damman.
REF9 “Larson Yacht Design Principles”: chapter 5: Hull Design pg 132. REF10 “Larson Yacht Design Principles”: chapter 7: Sail design
58 CORTO MALTESE 65
REF11 C.A. Marchaj: “Aero-Hydrodynamics of sailing” pg 89.
L2 Di = k • ΠAr REF12: MYD’40 “Hydrodynamic study of a canting keel based appendage configuration” by Lopez Pavon, Zamora Rodriguez,€ Perez Rojas. International Journal of Small Craft Technology: “practical aspect of canting keel design construction and analysis” by Tier, Owen, Sadler. The international HISWA Symposium on Yacht Design and Yacht Construction 2004: “Design Considerations for Canting Keel Yachts” by Claughton, Oliver. RINA: “Are dagger boards and trim tabs necessary when sailing with a canting keel?” by G.S. Barkley, Hudson, Turnock, Spinney. “Lifting line theory” prandthell
REF13: from “theory of wing sections” by IRA H. Abbot & A. E. Von Doenhoff.
REF14: Formulas from “Rudder design data for small craft” by A.F. Molloand: C dCL DC α CL = •α+ • (1) dα α =0 ARE 57.3 dC 2π L = Where α = 0 3 (2) dα 57.3*(1+ € ARe
C C = 0.1+ 0.7* T And € DC (3) CR
XC 2 (4) C = C + L D D0 AR € e
REF15: “Larson Yacht Design Principles”: Chapter 6 keel and rudder design Pg 105. Prandtl & Helmbold. €
59 CORTO MALTESE 65
REF16: “Lifting line theory” REF17: “NAvtec”: Navtec's main manufacturing facilities and corporate headquarters are located in Guilford, Connecticut. Make contact with Navtec, as you require.
Navtec Corporation 351 New Whitfield Street Guilford, CT 06437-0388 USA
Email: [email protected] REF18: “Larson Yacht Design Principles”: Chapter 11: Rig Construction.
19 REF : “Giles Barkley”. 3 12• DSPM /64 + LSM0 − 30 20 0,3048• MB REF : CI 18.75 2 3 = • − 3 SI = DSPM /64 3
Where: DSPM = Displacement in measured trim = 12315 kg € LSM0 = Second moment€ length calculated as 17,89. Restrictions: -5.0≤ CI≤ 5.0
SI≤ 10
RA90• DSPS BLRIndex = + 0.5 6• SA •CE Where: DSPS = Displacement in sailing trim = 13250 kg.
€ RA90 = Righting moment @ 90 degrees of heel in sailing trim taken as 1,992m. SA = Rated sail area = 280 m^2.
CE = Centre of effort estimated around 12m. LSM1 = second moment length in sailing trim = 18,4.
60 CORTO MALTESE 65
REF21: Corto Maltese (possibly derived from the Venetian Courtyard of the Maltese) is a laconic sea captain adventuring during the early 20th century (1900-1920s). A "rogue with a heart of gold," he is tolerant and sympathetic to the underdog. Born in Valletta on July 10, 1887, he is a son of a British sailor from Cornwall and a gypsy Andalusian prostitute known as "La Niña de Gibraltar". As a boy growing up in the Jewish quarter of Córdoba, Maltese realised he had no fate line on his palm and therefore carved his own with a razor, determining that his fate was his to choose. Although maintaining a neutral pose, Corto instinctively supports the disadvantaged and oppressed.
REF22: Cariboni Giovanni - Via Mattei 3/a - 20050 Ronco Briantino (MI) - P.IVA IT01475080139 - e-mail: [email protected] - tel. +39 039 6079609.
61 CORTO MALTESE 65
Appendix A
Drawing 1: Sail Plan Drawing 2: Interior Drawing 3: Structure A Drawing 4: Scantlings Drawing 5: Deck Plan & profile Drawing 6: Interior Sections A Drawing 7: Interior Sections B Drawing 8: Interior Sections C Drawing 9: Mast & Details Drawing 10: Hull Lines Drawing 11: Balance
Drawing 12: Water Planes Drawing 13: Structural lay out (Rhino Render)
62 CORTO MALTESE 65
Appendix B Appendix C Appendix D
63 Appendix B: parametrics database:
CORTO MALTESE 65
TAB 2: WEIGHT ESTIMATION LEVEL 1 ∆ (Kg)= 12000
PART 1 CANOE D (m) = 2,1
Items % Of tot W. Weight (Kg) Leaver % D Leaver (m) (V) Mom
Structure 10 1000 50 1,05 1050 Hull 15 1600 50 1,05 1680 Machinery (P) 3 200 25 0,525 105 Machinery (S1) 2 240 45 0,945 226,8 Machinery (S2) 0,8 50 25 0,525 26,25 Tank 1 0 0 10 0,21 0 Tank 2 0 0 10 0,21 0 Outfit 4 300 115 2,415 724,5 Crew 5 500 100 2,1 1050 Dead weights 2,8 150 45 0,945 141,75 Deck 8 850 100 2,1 1785 SUMS 50,6 4890 KG= 1,388 6789,3
PART 2 KEEL Tk (m) = 4,8 Tc= 0,44
Items % Of tot W. Weight (Kg) Leaver % Tk Leaver (m) (V) Mom
Keel fin 3 360 50 -2,18 -784,8 Bulb 53 6300 5 -3,96 -24948 Sums 6660 -25732,8 KG= -3,86
PART 3 MAST IK (m) = 33,1
Items % Of tot W. Weight (Kg) Leaver % Itot Leaver (m) (V) Mom
Mast 5 600 33 10,923 6553,8 Main 1 60 28 9,268 556,08 Jib 1 60 25 8,275 496,5 Spy 1 40 40 13,24 529,6 SUMS 760 KG= 10,705 8135,98
760 12310
VCG from Canoe Base line (m) -0,901 Appendix B: parametrics database:
Outfit 4 Crew 5 Dead weights 2,8 Deck 8 SUMS 19,8
PART 2 KEEL
Items % Of tot W.
Keel fin 3 Bulb 53 Sums
PART 3 MAST
Items % Of tot W.
Mast 5 Main 1 Jib 1 Spy 1 SUMS Appendix B: parametrics database:
#VALUE! #VALUE!
VCG from Canoe Base line (m) Appendix B: parametrics database: Appendix B: parametrics database:
300 115 6,555 1966,5 500 100 5,7 2850 150 45 2,565 384,75 850 100 5,7 4845 1800 KG= 5,581 10046,25
Tk (m) = 4,8 Tc= 0,44
Weight (Kg) Leaver % Tk Leaver (m) (V) Mom
#VALUE! 50 -2,18 #VALUE! 6300 5 -3,96 -24948 #VALUE! #VALUE! KG= #VALUE!
IK (m) = 33,1
Weight (Kg) Leaver % Itot Leaver (m) (V) Mom
#VALUE! 33 0 #VALUE! 60 28 0 0 60 25 0 0 40 40 0 0 #VALUE! KG= #VALUE! #VALUE! Appendix B: parametrics database:
#VALUE! Appendix B: parametrics database: Appendix B: parametrics database:
CORTO MALTESE 65
TAB 2: WEIGHT ESTIMATION LEVEL 1 ∆ (Kg)= 12000
PART 1 CANOE D (m) = 2,1
Items % Of tot W. Weight (Kg) Leaver % D Leaver (m) (V) Mom
Structure 10 1000 50 2,85 2850 Hull 15 1600 50 1,05 1680 Machinery (P) 3 200 25 1,425 285 Machinery (S1) 2 #VALUE! 45 2,565 #VALUE! Machinery (S2) 0,8 50 25 1,425 71,25 Tank 1 0 #VALUE! 10 0,57 #VALUE! Tank 2 0 #VALUE! 10 0,57 #VALUE! Appendix B: parametrics database: CORTO MALTESE IRC65 APPENDIX C: CORTO MALTESE IRC65 APPENDIX C:
Hull scant out put:
Carbon Mast Data allspars Masts & Rigging
Carbon Masts>> Mast Section El El Wall Weight W W y x y x section dim. 2 2 thickness kg/mm 3 3 mm GNmm GNmm mm cm cm CC154-30 157/87 230 92 3.0 1.8 40 30 CC154-36 158/88 292 117 3.6 2.2 49 37 CC1 74-30 177/93 325 120 3.0 2.0 51 37 CC174-36 178/94 411 152 3.6 2.4 61 44 CC192-36 195/102 533 194 3.6 2.6 72 52 CC192-42 196/103 644 235 4.2 3.1 85 61 CC21O-36 213/110 688 242 3.6 2.9 85 61 CC21O-42 214/111 832 293 4.2 3.4 100 71 CC226-36 228/118 849 301 3.6 3.1 98 70 CC226-42 229/119 1025 365 4.2 3.6 115 82 CC244-42 247/127 1282 448 4.2 3.9 134 95 CC244-48 248/128 1503 527 4.8 4.5 153 109 CC263-48 266/136 1844 638 4.8 4.8 176 124 CC263-54 267/137 2116 735 5.4 5.4 199 140 CC284-48 286/146 2314 800 4.8 5.1 205 145 CC284-54 288/147 2653 920 5.4 5.8 231 163 CC303-54 306/156 3203 1107 5 4 6.2 262 185 CC303-60 307/158 3613 1253 6.0 6.9 292 206
Including track Including track and lx 300 Including track and 1)2)3) gsm 100 mm wide 0° tape 2x300gsm 100mm wide 0° front and back tapes front and back Mast El Weight El Weight El Weight y y y section 2 kg/m 2 kg/m 2 kg/m GNmm GNmm GNmm CC154-30 302 2.3 335 2.4 365 2.5 CC154-36 367 2.7 399 2.8 432 2.9 CC174-30 418 2.5 460 2.6 501 2.7 CC1 74-36 508 2.9 550 3.0 594 3.1 CCI 92-36 648 3.1 699 3.2 751 3.3 CC1 92-42 763 3.6 815 3.7 867 3.8 CC210-36 824 3.4 887 3.5 951 3.6 CC210-42 972 3.9 1036 4.0 1099 4.0 CC226-36 1005 3.6 1078 3.7 1152 3.8 CC226-42 1185 4.1 1259 4.2 1335 4.3 Including track Including track and Including track and 4x300 1) 2) 3) 2x300gsm 100mm wide 0° gsm 100 mm wide 0° tapes tape front and back front and back El Weight El Weight El Weight Mast y y y 2 kg/m 2 kg/m 2 kg/m section GNmm GNmm GNmm CC244-42 1467 4.4 1641 4.6 1812 4.7 CC244-48 1691 5.0 1868 5.1 2044 5.3 CC263-48 2061 5.3 2264 5.4 2470 5.6 CC263-54 2336 5.9 2542 6.1 2750 6.2 CC284-48 2564 5.6 2804 5.8 3041 6.0 CC284-54 2907 6.3 3150 6.5 3393 6.7 CC303-54 3488 6.7 3762 6.9 4034 7.0 CORTO MALTESE IRC65 APPENDIX C:
Carbon Mast Data allspars Masts & Rigging
Carbon Masts>> Mast Section El El Wall Weight W W y x y x section dim. 2 2 thickness kg/mm 3 3 mm GNmm GNmm mm cm cm CC154-30 157/87 230 92 3.0 1.8 40 30 CC154-36 158/88 292 117 3.6 2.2 49 37 CC1 74-30 177/93 325 120 3.0 2.0 51 37 CC174-36 178/94 411 152 3.6 2.4 61 44 CC192-36 195/102 533 194 3.6 2.6 72 52 CC192-42 196/103 644 235 4.2 3.1 85 61 CC21O-36 213/110 688 242 3.6 2.9 85 61 CC21O-42 214/111 832 293 4.2 3.4 100 71 CC226-36 228/118 849 301 3.6 3.1 98 70 CC226-42 229/119 1025 365 4.2 3.6 115 82 CC244-42 247/127 1282 448 4.2 3.9 134 95 CC244-48 248/128 1503 527 4.8 4.5 153 109 CC263-48 266/136 1844 638 4.8 4.8 176 124 CC263-54 267/137 2116 735 5.4 5.4 199 140 CC284-48 286/146 2314 800 4.8 5.1 205 145 CC284-54 288/147 2653 920 5.4 5.8 231 163 CC303-54 306/156 3203 1107 5 4 6.2 262 185 CC303-60 307/158 3613 1253 6.0 6.9 292 206
Including track Including track and lx 300 Including track and 1)2)3) gsm 100 mm wide 0° tape 2x300gsm 100mm wide 0° front and back tapes front and back Mast El Weight El Weight El Weight y y y section 2 kg/m 2 kg/m 2 kg/m GNmm GNmm GNmm CC154-30 302 2.3 335 2.4 365 2.5 CC154-36 CC309-367 80 2.7 4547 399 7,8 2.8 4876432 82.9 CC174-30 418 2.5 460 2.6 501 2.7 CC1 74-36 508 2.9 550 3.0 594 3.1 CCI 92-36 648 3.1 699 3.2 751 3.3 CC1 92-42 763 3.6 815 3.7 867 3.8 CC210-36 824 3.4 887 3.5 951 3.6 CC210-42 972 3.9 1036 4.0 1099 4.0 CC226-36 1005 3.6 1078 3.7 1152 3.8 CC226-42 1185 4.1 1259 4.2 1335 4.3 Including track Including track and Including track and 4x300 1) 2) 3) 2x300gsm 100mm wide 0° gsm 100 mm wide 0° tapes tape front and back front and back El Weight El Weight El Weight Mast y y y 2 kg/m 2 kg/m 2 kg/m section GNmm GNmm GNmm CC244-42 1467 4.4 1641 4.6 1812 4.7 CC244-48 1691 5.0 1868 5.1 2044 5.3 CC263-48 2061 5.3 2264 5.4 2470 5.6 CC263-54 2336 5.9 2542 6.1 2750 6.2 CC284-48 2564 5.6 2804 5.8 3041 6.0 CC284-54 2907 6.3 3150 6.5 3393 6.7 CC303-54 3488 6.7 3762 6.9 4034 7.0 CORTO MALTESE IRC65 APPENDIX C: CORTO MALTESE IRC65 APPENDIX C: CORTO MALTESE IRC65 APPENDIX C: CORTO MALTESE IRC65 APPENDIX C: CORTO MALTESE IRC65 APPENDIX C: CORTO MALTESE 65 APPENDIX C
STRUCTURAL WEIGHTS AND CENTERS ESTIMATION :
Bo om region : weigth (kg/m^2)= 8,193 leaver and center from a per & lwl
Pannel n. l (mm) b (mm) l (m) b (m) area (m^2) weight (kg) Long leaver (m) Vert Leaver (m) 1 1585 605 1,585 0,605 0,959 7,856 11 86,421 ‐0,43 ‐3,378 2 583 828 0,583 0,828 0,483 3,955 9,87 39,035 ‐0,42 ‐1,661 3 2498 925 2,498 0,925 2,311 18,931 8,24 155,993 ‐0,37 ‐7,005 4 1054 600 1,054 0,6 0,632 5,181 6,42 33,264 ‐0,34 ‐1,762 5 1054 972 1,054 0,972 1,024 8,394 6,42 53,887 ‐0,24 ‐2,014 6 1950 600 1,95 0,6 1,170 9,586 5,06 48,504 ‐0,34 ‐3,259 7 1950 1376 1,95 1,376 2,683 21,983 5,06 111,236 ‐0,24 ‐5,276 8 1931 1380 1,931 1,38 2,665 21,833 3,32 72,484 ‐0,19 ‐4,148 9 1931 600 1,931 0,6 1,159 9,492 3,32 31,515 ‐0,26 ‐2,468 10 1889 600 1,889 0,6 1,133 9,286 1,11 10,307 ‐0,15 ‐1,393 11 1889 1250 1,889 1,25 2,361 19,346 1,11 21,474 ‐0,086 ‐1,664 12 987 1420 0,987 1,42 1,402 11,483 ‐0,32 ‐3,675 0,036 0,413 13 987 14 15 16 17 18 TOT w 147,326 660,446 ‐33,615
fnal long leaver 4,483 f vert leaver ‐0,228
Chine region weight (kg/m^2) 7,764
Pannel n. l (m) b (m) area (m^2) weight (kg) Long leaver (m) Vert Leaver (m) Shell final :
1 2,71 0,953 2,583 20,052 12,99 260,4695 0,16 3,208 item: weight (kg) 10% L l. (m) V l. (m) 2 1,585 1,014 1,607 12,478 11,003 137,2979 0,18 2,246 3 0,583 1,071 0,624 4,848 9,874 47,86705 0,18 0,873 bo om 147,326 162,0586 726,4898 ‐36,976 4 2,498 1,074 2,683 20,830 8,244 171,7197 0,233 4,853 chine 152,841 168,1251 1009,396 92,108 5 1,054 1,54 1,623 12,602 6,426 80,982 0,104 1,311 side 77,43 85,173 1090,672 97,443 6 1,95 1,54 3,003 23,315 5,06 117,975 0,896 20,891 b slam 46,869 51,55554 787,835 ‐11,844 7 1,93 1,59 3,069 23,825 3,323 79,172 0,901 21,467 tot w (kg) 466,9122 3614,393 140,732 8 1,889 1,59 3,004 23,319 1,11 25,884 0,812 18,935 9 0,987 1,51 1,490 11,571 ‐0,323 ‐3,738 0,86 9,951 Long leaver (m) 7,741 W x2 933,8245 Vert Leaver (m) 0,301 917,630 83,735 tot w 152,841 L leaver 6,004 v leaver 0,548 CORTO MALTESE 65 APPENDIX C
Side region : weight of laminate used (kg/m^2)= 6,42
Pannel n. l (m) b (m) area (m^2) weight (kg) Long leaver (m) Vert Leaver (m)
1 2,49 1,08 2,689 17,26466 8,244 142,3299 1,035 17,869 2 0,583 0,917 0,535 3,432203 9,874 33,88957 1,186 4,071 3 1,595 1,007 1,606 10,31158 11,002 113,448 1,187 12,240 4 2,7 1,036 2,797 17,95802 12,994 233,3466 1,192 21,406 5 2,697 1,24 3,344 21,47028 16,092 345,4997 1,123 24,111 6 1,068 1,02 1,089 6,993691 17,589 123,012 1,271 8,889
tot w 77,43044 991,5258 88,585
l leaver 12,805 1,144
Longitudinal s ffner : item L (m) bc (mm) bb (mm) h (mm) Area (mm^2)Area m^2 w est (kg/m) W (kg) L leaver V leaver CL G 11,114 250 300 300 82500 0,0825 9,56 106,200 12,54 1331,75 ‐0,22 ‐23,3641 S G 1 4,666 150 200 150 26250 0,02625 9,93 46,314 9,36 433,50 ‐0,191 ‐8,846045 S G 2 7,812 150 200 150 26250 0,02625 9,93 77,541 6,94 538,14 0,173 13,41465 D G 16,998 150 200 150 26250 0,02625 9,93 168,721 8,676 1463,82 1,62 273,3278 S S 1 6,475 125 150 150 20625 0,020625 9,96 64,510 14,927 962,94 0,695 44,83458 S S 2 7,375 125 150 150 20625 0,020625 9,96 73,477 10,72 787,67 0,7315 53,74832
536,764 5517,83 353,1152
10,28 0,66 bulk heads: weight of laminate (kg/m^2)= 7,067 frame area m^2 W kg % l.leaver v. leaver
A 0,917 6,480 1 6,480 17,100 110,8129 0,908 5,884 B 3,463 24,473 0,56 13,705 14,402 197,3806 0,814 11,153 C 6,075 42,932 0,56 24,042 11,693 281,1127 0,746 17,938 D 7,274 51,405 0,7 35,984 10,108 363,7273 0,726 26,135 E 7,268 51,363 0,7 35,954 9,525 342,4625 0,722 25,973 F 8,56 60,494 0,56 33,876 7,027 238,0493 0,722 24,472 G 8,67 61,271 0,56 34,312 5,973 204,9438 0,729 25,020 H 8,41 59,433 0,56 33,283 4,023 133,8832 0,749 24,939 I 7,53 53,215 0,56 29,800 2,092 62,34 0,779 23,211 L 6,14 43,391 1 43,391 0,208 9,02 0,818 35,481
tot w 290,827 1943,729 220,206
tot l leaver (m) 6,683446 tot v Leaver (m) 0,757171 CORTO MALTESE 65 APPENDIX C
bo om slamming: Weight (kg/m^2)= 9,38
Pannel n. l (m) b (m) area(m^2) weight (kg) Long leaver (m) Vert Leaver (m) 1 1,073 0,62 0,665 6,240 17,59 109,764 0,22 1,373 2 2,75 0,984 2,706 25,382 16,09 408,401 ‐0,22 ‐5,584 3 2,7 0,602 1,625 15,246 12,99 198,049 ‐0,43 ‐6,556
totmw kg= 46,869 sum 716,214 ‐10,767
L leaver 15,281 v leaver ‐0,230
Final stucture item weight (kg) L.l(m) V.l (m) shel 933,82 7,74 7228,751 0,30 281,46 deck 557,55 6,79 3785,098 1,54 861,34 long s f 536,764 10,28 5517,83 0,66 353,12 bulk 290 6,68 1938,199 0,757171 219,58 sum 18469,88 sum 1715,50 tot w kg 2318,134 Longitudinal. (m) 7,97 V. l. (m) 0,74 CORTO MALTESE 65 APPENDIX C
Cockpit pannel weight (kg/m^2) 6,017
Pannel n. l (m) b (m) area (m^2) weight (kg) Long leaver (m) Vert Leaver (m) 1 0,98 1,373 1,345 8,093 6,4266 52,01 1,194 9,66 2 1,914 1,593 3,049 18,345 5,062 92,86 1,194 21,90 3 1,914 1,697 3,249 19,548 3,323 64,96 1,194 23,34 4 1,913 2,255 4,314 25,956 1,1095 28,80 1,063 27,59 6 1 2,120 2,120 12,756 ‐0,328 ‐4,18 0,9615 12,26 7 0,98 0,545 0,534 3,211 6,4266 20,64 1,3995 4,49 8 1,914 0,545 1,042 6,272 5,062 31,75 1,3995 8,78 9 1,914 0,545 1,042 6,272 3,323 20,84 1,3995 8,78
tot w kg 100,453 307,67 116,81
3,063 1,163
Normal deck pannel weight (kg/m^2) 6,107
Pannel n. l (m) b (m) area (m^2) weight (kg) Long leaver (m) Vert Leaver (m) 1 1,913 0,369 0,706 4,311 1,11 4,785 1,568 6,760 2 1,913 0,369 0,706 4,311 1,11 4,785 1,681 7,247 3 2,6 0,577 1,500 9,162 8,244 75,529 1,709 15,657 4 2,6 0,592 1,539 9,400 8,244 77,493 1,742 16,375 5 2,7 0,528 1,426 8,706 12,994 113,128 1,727 15,036 6 2,7 1,048 2,830 17,280 12,994 224,541 1,82 31,450
reinforced deck: pannel weight (kg/m^2) 6,017
53,170 500,261 92,524 Pannel n. l (m) b (m) area (m^2) weight (kg) Long leaver (m) Vert Leaver (m) 1 1,914 0,54 1,034 6,219 3,323 20,67 1,699 10,57 l le (m) 9,409 1,740 2 1,914 0,54 1,034 6,219 3,323 20,67 1,699 10,57 3 1,914 0,54 1,034 6,219 5,062 31,48 1,699 10,57 4 1,914 0,54 1,034 6,219 5,062 31,48 1,699 10,57 5 0,986 0,54 0,532 3,204 6,427 20,59 1,699 5,44 Deck final: 6 0,986 0,54 0,532 3,204 6,427 20,59 1,699 5,44 7 2,18 0,538 1,173 7,057 10,68 75,37 1,765 12,46 item: weight (kg) 10% L l. (m) V l. (m) 8 2,18 0,504 1,099 6,611 10,68 70,61 1,701 11,25 9 2,751 0,454 1,249 7,515 16,092 120,93 1,773 13,32 n D 53,170 58,487 550,287 101,776 10 2,751 0,454 1,249 7,515 16,092 120,93 1,811 13,61 R D 99,809 109,789 1003,822 200,400 11 1,074 0,2198 0,236 1,420 17,389 24,70 1,815 2,58 Co &de 100,453 110,499 338,4405 128,4943 12 4,828 0,6872 3,318 19,963 9,2316 184,29 1,889 37,71 13 4,828 0,6349 3,065 18,444 9,2316 170,27 2,0662 38,11 tot w (kg) 278,775 1892,550 430,671 99,809 912,566 182,182 Long leaver (m)6,788805 W x2 557,5501 Vert Leaver (m)1,544868 9,14 1,83 CORTO MALTESE 65 APPENDIX C CORTO MALTESE 65 APPENDIX C Tab 8.2: 12217-3: Sailing7.2 boats Downflooding height at equilibrium Pass the min. freeboardDownfloodingPoints of the shall be greater than (>) 0,5 m 1,225 Pass
11.3 Damage Stability11.3.1.1 Equilibrium waterline Pass the min. freeboardDeckEdge of the shall be greater than (>)0,075 m 0,162 Pass
12217-3: Sailing7.5 boats Knockdown-recovery test (angle of vanishing stability Passin flooded condition) shall be greater than (>)115 deg 123,7 Pass
12217-3: Sailing7.6.6 boats Wind stiffness test (angle of equilbrium with heel armPass less than specified value) Heeling arm = A cos^n(phi) A = 2 m n = 1,3 shall be less than (<) 45 deg 6,7 Pass
11.2.1.1 Monohulls11.2.1.1.1a Area 0 to 30 Pass from the greater of spec. heel angle 0 deg 0 to the lesser of spec. heel angle 30 deg 30 angle of vanishing stability123,7 deg shall not be less than (>=)3,151 m.deg 68,68 Pass
11.2.1.1 Monohulls11.2.1.1.1b Area 0 to 40 Pass from the greater of spec. heel angle 0 deg 0 to the lesser of spec. heel angle 40 deg 40 first downfloodingn/a angle deg angle of vanishing stability123,7 deg shall be greater than (>)5,157 m.deg 96,536 Pass
11.2.1.1 Monohulls11.2.1.1.2 Area 30 to 40 Pass from the greater of spec. heel angle 30 deg 30 to the lesser of spec. heel angle 40 deg 40 first downfloodingn/a angle deg angle of vanishing stability123,7 deg shall be greater than (>)1,719 m.deg 27,855 Pass
11.2.1.1 Monohulls11.2.1.1.3 Max GZ at 30 or greater Pass in the range from the greater of spec. heel angle 30 deg 30 to the lesser of spec. heel angle 180 deg angle of max. GZ 47 deg 47 shall be greater than (>) 0,2 m 2,842 Pass Intermediate values angle at which this GZ occursdeg 47
11.2.1.1 Monohulls11.2.1.1.4 Angle of maximum GZ Pass shall not be less than (>=)25 deg 47 Pass
11.2.1.1 Monohulls11.2.1.1.5 Initial GMt Pass spec. heel angle 0 deg shall not be less than (>=)0,15 m 3,738 Pass
CORTO MALTESE 65
Appendix C Rudder stock calculation according ISO 12215-8: area 9(m^2) A 2,025 hr 1,8 hc 0,05 b1 0,5 b2 0,2 kb 0,43 zb 0,7955 t 0,005 c 0,4 u 0,15 frw 1 mcdc 13500 v 14,20 vmin 10,27 lwl 18,3 kv 1,512 ae 1,6 r 0,05 Cr 1,26 F 69346 M 55164 T 3467 Yiel stress 830 ultimate tensile strenght 900 design strees 450 Km 0,731
Z eq (m) 0,7967 D 316 (mm) 147 d (mm) 108 CORTO MALTESE 65 CORTO MALTESE 65 TAB 8.1: Tab 8.1 Weight estimationn for the interior: NOTE: Long. Leavers are from aft per Weight estimationn for the Deck: NOTE: Long. Leavers are from aft per
N. : Item: Weight W (kg): Long Leaver l. (m): Vert. Leaver v. (m): N. : Item: Weight W (kg): Long Leaver l. (m): Vert. Leaver v. (m): 1 Rudder stock + bear. 240 0,57 136,8 0,17 40,8 1 pulpiti 5 0,51 2,55 1,51 7,55 2 Carbon quadrant 2 0,57 1,14 0,15 0,3 2 Spinaker Pull 0,3 0,03 0,009 1,51 0,453 3 bench 1 10 1,18 11,8 0,42 4,2 3 Main rail 3 1,23 3,69 1,12 3,36 4 benchs 2 20 3,07 61,4 0,64 12,8 4 Main PULL 1,2 1,23 1,476 1,2 1,44 5 benchs 3 20 5 100 0,64 12,8 5 Runners winch 36 1,49 53,64 1,7 61,2 6 benchs 4 20 8,02 160,4 0,64 12,8 6 pulpiti 1 16 7,25 116 1,75 28 7 Stairs E 4 1,42 5,68 0,51 2,04 7 Main winch & s. 23 2,1 48,3 1,64 37,72 8 Storage aft 1 100 5,36 536 0,095 9,5 8 Main r. w. 36 2,76 99,36 1,67 60,12 9 Storage aft 2 360 6,45 2322 0,57 205,2 9 Main Grinder 5 3,29 16,45 1,62 8,1 10 Engine 240 6,45 1548 0,097 23,28 10 Lewmar 1 10 1,5 15 1,42 14,2 11 Battery 100 6 600 0,14 14 11 Rudder pillars 5 1,18 5,9 1,12 5,6 12 Pump system 15 6 90 -0,23 -3,45 12 JIB winch & s. 54 5,41 292,14 1,76 95,04 13 Stairs 1 7 7,4 51,8 0,38 2,66 13 Console winch 36 6,63 238,68 1,75 63 14 Water maker 20 5,36 107,2 0 0 14 Console 3 7,23 21,69 1,77 5,31 15 Tank 1 fuel 100 7,41 741 -0,25 -25 15 Jib rail 6 9,919 59,514 1,77 10,62 16 Tank 2 Fw 200 8,55 1710 -0,23 -46 16 Chain plates 12 9,54 114,48 1,68 20,16 17 Chart table 5 9 45 0,767 3,835 17 Lewmar 2 10 14,12 141,2 1,83 18,3 18 Instruments 20 9,4 188 0,96 19,2 18 Chain plates 12 17,28 207,36 1,74 20,88 19 CK device box 240 9,83 2359,2 0,12 28,8 19 furlex system 3 17,28 51,84 1,94 5,82 20 WC + washer 15 10,7 160,5 0,36 5,4 20 bow spirit 3 18,93 56,79 1,74 5,22 21 Cooker + washer 15 10,7 160,5 0,64 9,6 21 Pulpito Bow 5 17,28 86,4 1,9 9,5 22 gas 5 10,07 50,35 0,1 0,5 22 Cockpit hatches 15 5 75 1,37 20,55 23 Fire extinguisher 10 7,023 70,23 0,1 1 23 Vang 15 9,48 142,2 2,49 37,35 24 First Aid 15 11,37 170,55 0,32 4,8 24 Boom 40 5,54 221,6 2,72 108,8 25 Storage FW 360 11,37 4093,2 0,64 230,4 26 Cannards boxes 100 12,17 1217 0,66 66 ToT W 354,5 2071,269 648,293 27 Stairs 2 5 14,11 70,55 0,78 3,9 28 Sails 300 13,05 3915 0,33 99 Vert l.(m) 5,84 Long. V.(m) 1,83 Tot W (Kg): 2548 20683 738,365 Final l.(m): 8,12 final v. (m) 0,29
Weight estimationn for the Appendages: Estimation of center of lateral resistance(CLR)
N Item W l. (m) v.(m) t.(m) N item area leaver 1 rudders 74 0,57 -0,743 42,18 -54,982 1 hull 6,5716 10,41 68,41036 2 keel 318 9,83 -3,485 3125,94 -1108,23 -2,232 2 rudder 0,6983 0,4545 0,317377 3 bulb 6340 9,4 -3,64 59596 -23077,6 -2,347 3 dagger boards1,7348 12,6426 21,93238 4 cannards 180 12,643 -1,884 2275,74 -339,12 9,0047 90,66012 Tot W (kg) 6912 65039,86 -24579,9 l 9,410 l (m) 10,06809 v -3,556 t -2,345 CORTO MALTESE 65 TAB 8.1: Corto Maltese IRC 65
Issue date: 16/05/09 Scale: 1:50 File name: Corto Maltese
Drawn by: G. Giotto Units: Meters Projection method: n.a. Drawing number: 12 Drawing title: water planes Edition: n.a. Sheet: 12 of 11 Corto Maltese IRC 65
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Issue date: 16/05/09 Scale: 1:100 File name: Corto Maltese
Drawn by: G. Giotto Units: Meters Projection method: n.a.
Drawing number: 11 Drawing title: Balance Edition: Sheet: 1 of 11 Corto Maltese IRC 65
Drawing number: Drawing Issue date: Issue Edition: Drawn by: n.a. G. Giotto 16/05/09 Units: Sheet: of Scale: Meters 5 1:50 11 5 Drawing title: Drawing File name: Projection method: n.a. IRC 65 Maltese Corto Deck plan & profile plan Deck Corto Maltese Corto Corto Maltese IRC 65
Issue date: 16/05/09 Scale: 1:50 File name: Corto Maltese Drawn by: G. Giotto Units: Meters Projection method: n.a. Drawing number: 2 Drawing title: INterIor Edition: n.a. Sheet: 2 of 11
Drawing number: Drawing Issue date: Issue Edition: Drawn by: n.a. G. Giotto 16/05/09 Units: Sheet: of Scale: Meters 1:50 9 11 9 Drawing title: Drawing File name: Projection method:
n.a. IRC 65 Maltese Corto
Mast & details Mast Corto Maltese Corto
Corto Maltese IRC 65
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Issue date: 16/05/09 Scale: 1:100 File name: Corto Maltese
Drawn by: G. Giotto Units: Meters Projection method: n.a.
Drawing number: 1 Drawing title: Balance Edition: Sheet: 1 of 11 Corto Maltese IRC 65
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Issue date: 16/05/09 Scale: 1:50 File name: Corto Maltese
Drawn by: G. Giotto Units: Meters Projection method: n.a. Drawing number: 4 Drawing title: ScantlingS Edition: n.a. Sheet: 4 of 11 Corto Maltese IRC 65
Issue date: 16/05/09 Scale: 1:50 File name: Corto Maltese
Drawn by: G. Giotto Units: Meters Projection method: n.a.
Drawing number: 6 Drawing title: InterIor sectIons A
Edition: n.a. Sheet: 6 of 11 Corto Maltese IRC 65
Issue date: 16/05/09 Scale: 1:50 File name: Corto Maltese
Drawn by: G. Giotto Units: Meters Projection method: n.a.
Drawing number: 7 Drawing title: InterIor sectIons B Edition: n.a. Sheet: 7 of 11 Corto Maltese IRC 65
Issue date: 16/05/09 Scale: 1:50 File name: Corto Maltese Drawn by: G. Giotto Units: Meters Projection method: n.a.
Drawing number: 8 Drawing title: InterIor sectIons c Edition: n.a. Sheet: 8 of 11 Corto Maltese IRC 65
Issue date: 16/05/09 Scale: 1:50 File name: Corto Maltese
Drawn by: G. Giotto Units: Meters Projection method: n.a.
Drawing number: 3 Drawing title: Structure A Edition: n.a. Sheet: 3 of 11 Corto Maltese IRC 65
Issue date: 16/05/09 Scale: 1:50 File name: Corto Maltese
Drawn by: G. Giotto Units: Meters Projection method: n.a. Drawing number: 10 Drawing title: Hull lines Edition: n.a. Sheet: 9 of 11 Corto Maltese IRC 65
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Issue date: 16/05/09 Scale: 1:50 File name: Corto Maltese
Drawn by: G. Giotto Units: Meters Projection method: n.a. Drawing number: 4 Drawing title: ScantlingS Edition: n.a. Sheet: 4 of 11