THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Symposium Schedule

Time DAY 1 - Friday, 15 June 2012 7:00 Registration Begins 7:30 Continental Breakfast Dean M. Schleicher 8:00 Bringing Science and Technology to the Waterfront – Donald L. Blount Daniel Savitsky 8:45 The Effect Of Bottom Warp On The Performance Of Planing Hulls Toru Katayama, Yoshitaka Nishihara, Takuya Sato 9:30 A Study On The Characteristics Of Self-Propulsion Factors Of Planing Craft With Outboard Engine 10:15 BREAK Ron Grifka 10:30 Practical Application Of Interceptors On A Small Non-Planing Powerboat Gregory J. White, William E. Beaver, David N. Vann 11:15 An Experimental Analysis Of The Effects Of Steps On High Speed Planing Boats 12:00 LUNCH John Zseleczky 1:00 Behind The Scenes Of Peak Acceleration Measurements Michael R. Riley, Timothy W. Coats 1:45 A Simplified Approach For Analyzing Rigid Body Accelerations Induced By Wave Impacts In High- Speed Planing Craft 2:30 BREAK Leigh McCue, Don Jacobson, Charles Weil, John Zseleczky 2:45 A Look At The Impact Of Filter Selection On Peak Identification Of High Speed Craft Vertical Accelerations Michael R. Riley, Timothy W. Coats 3:30 A Method For Computing Wave-Impact Equivalent Static Accelerations For Use In Planing Craft Hull Design Eric Giesberg, Raju Datla 4:15 Development Of Empirical Equations For Planing Craft Motions In Irregular Waves Through Genetic Algorithms 5:00 ADJOURN

Papers That Will Qualify For SNAME Continuing Education Points Resistance and Propulsion Seakeeping THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Symposium Schedule

Time DAY 2 - Saturday, 16 June 2012 7:00 Registration Begins 7:30 Continental Breakfast Carolyn Q. Judge 8:00 Static And Dynamic Forces And Wetted Lengths For A Planing Hull Model Forced In Roll Christopher S. Chaney, Konstantin I. Matveev 8:45 Modeling Of Vertical-Plane Motions Of Tunnel Hulls Jeffrey Bowles 9:30 Turning Characteristics And Capabilities Of High-Speed Monohulls William Burns, T.J. Perrotti, Chris Todter, Daniel Casal, Johnny Smullen, John G. Hoyt III 10:15 M ’s Rapid Empirical Innovation (Rei) Open Water Model Test Platform Romain Garo, Raju Datla, Leonard Imas 11:00 Numerical Simulation Of Planing Hull Hydrodynamics Thomas T. O’Shea, Kyle A. Brucker, Donald Wyatt, Douglas G. Dommermuth, Thomas C. Fu 11:45 A Detailed Validation Of Numerical Flow Analysis (Nfa) To Predict The Hydrodynamics Of A Deep-V Planing Hull 12:30 LUNCH Frank DeBord, Karl Stambaugh, Chris Barry, Eric Schmid 1:15 Evaluation Of High-Speed Craft Designs For Operations In Survival Conditions Tony Caiazzo, Sid Charbonnet, Lou Codega 2:00 Design, Construction And Testing Of The Advanced Composite Riverine Craft Albert Nazarov 2:45 On Application Of Parametric Method For Design Of Planing Craft Jan Alexander Keuning 3:30 Improved design of a Search And Rescue boat for the Royal Lifeboat Institution Christopher D. Barry 4:15 Composite Techniques For Affordable Limited Production, Sustainable High Performance Yacht Construction; Not What You Might Think 5:00 ADJOURN

Papers That Will Qualify For SNAME Continuing Education Points Dynamics and Testing Techniques Numerical Analysis and Computational Fluid Dynamics Design and Production THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Abstracts

Dean M. Schleicher Bringing Science and Technology to the Waterfront – Donald L. Blount

Donald Blount is recognized around the world for his contributions to high-speed marine vehicles of various types for more than 50 years. A highlight of his career has been the revolutionary high-speed craft, DESTRIERO, which holds the combined east and west bound Atlantic crossing elapsed time record and the fastest east bound crossing record for which its development history has been resented in numerous forums. An in-depth look at his career beyond this singular achievement will be shared in honor of his numerous contributions to the marine industry during his lifetime of bringing science and technology to the waterfront.

Daniel Savitsky The Effect Of Bottom Warp On The Performance Of Planing Hulls

The hydrodynamic lift, wetted area and center of pressure of a constant beam, warped bottom planing surface were obtained experimentally for a model having a 3 deg./beam increase of deadrise from 10 deg. at the transom to 30 deg at the stem (typical for the planing area of a warped hull). Towing tank tests of this warped bottom hull were conducted over a wide range of speeds, trim angles and wetted lengths. An analysis of the data indicated that established planing equations for prismatic hulls are also suitable for this warped hull if the effective deadrise of the warped hull is taken to be that at the mean wetted length of the bottom area. Also, the effective trim angle is not the keel angle relative to the level water surface but is the angle of the ¼ buttock line (at the mean wetted length position) relative to the level water surface. Published equations for prismatic planing hulls have shown that the longitudinal position of the mean wetted length (relative to the transom) is a known function of the longitudinal position of the center of bottom pressure and the speed coefficient. It is independent of trim angle or deadrise angle. Hence, assuming that the LCG of the craft is located at the longitudinal center of pressure and the thrust moment is small, the mean wetted length is easily determined. Locating this distance on the lines plan of a warped hull identifies the effective deadrise and trim angle of an equivalent prismatic hull to be used with published planing equations. Using these observations, a procedure is provided for estimating the smooth water performance of warped planing hulls. Two examples are provided and show that the analytical results agree with model data obtained at the Davidson Laboratory. Also a comparison in made with model data obtained at MARIN on tests of a 70 ft. long warped planing hull and show equally good correlation. If the reference deadrise angle is taken to be that at the transom, it is shown that the use of warp in the planing area deteriorates the planing efficiency of the hull.

Toru Katayama, Yoshitaka Nishihara, Takuya Sato A Study On The Characteristics Of Self-Propulsion Factors Of Planing Craft With Outboard Engine

The purpose of this study is to develop a method to estimate propulsive performance for planing craft with outboard engines. In order to understand the characteristics of this form of propulsion, a fully captive model test system with propulsion was developed and tested. And the effects of the changes in hydrodynamic forces and moments acting on hull due to the interaction with the lower-hull of the outboard engine and its propeller, as well as the effective wake fraction and the relative rotative efficiency, is presented. Based on the experimental results, an estimation method is proposed. By using the proposed method, running attitude (or trim and rise), thrust (or THP; Thrust Horse Power), crank shaft torque (or BHP; Braking Horse Power), maximum forward speed and fuel consumption of a real craft are estimated. It was found that the effective wake fraction and the relative rotative efficiency have significant impact on the estimate of maximum forward speed of the craft. THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Abstracts

Ron Grifka Practical Application Of Interceptors On A Small Non-Planing Powerboat

A surplus U.S. Coast Guard 26 foot Motor Surf Boat (MSB) was purchased and outfitted for use as a pleasure craft. This boat had been previously repowered by the Coast Guard and is capable of considerably higher speeds than the original design. The hull form has curved buttocks aft and a rounded transom which caused excessive trim at these higher speeds. The owner investigated a number of possible solutions to correct this excessive trim and selected installation of a fixed interceptor. This solution was believed to be simpler than installation of trim tabs, especially considering the rounded shape of the transom. However, there were two areas of uncertainty related to use of this devise on the MSB: (1) would an interceptor be effective on this hull form at the pre-planing and planning speeds; and (2) what size interceptor would be required to correct the trim problem? The following were the design considerations (1) the total project cost must be less than $3,500 (2) The design must be able to allow for the installation of different interceptors with out hauling the boat out of the water (3) the interceptor must be able to be removed from the boat leaving no trace of it’s existence if it did not improve the boats performance. To determine the length of the interceptor the transom was marked at 4 inch intervals off the center line of the transom to aid in visual observation of water flow and set of pictures were taken of the stern wake as well as the water flow off the transom .It was believed that a minimum depth of an inch would be need to interrupt the water flow. Expectations (1) the interceptor would have no effect on the boat at run angle under 1500 RPM and would only present a small fuel penalty (2) the interceptor would be effective above 1500 RPM and make the boat more mannerly. A relatively small interceptor was found to be very effective reducing trim, improving fuel consumption and increasing maximum speed. This paper presents design details and trials results quantifying the performance improvements.

Gregory J. White, William E. Beaver, David N. Vann An Experimental Analysis Of The Effects Of Steps On High Speed Planing Boats The hard chine, deep-vee hull form has been used in a wide variety of commercial and naval applications for a number of years. The hull form offers advantages in stability, speed, and wide beam for large cockpit areas. There are also several disadvantages associated with the hull form, most notably the large motions and accelerations in a seaway. In recent years the high speed boat racing community has adopted transverse steps in the after bottom surfaces of the hulls to introduce air pockets and reduce drag. The size, number, and location of the steps have varied, but the concept of stepped-hulls has become a standard for high speed craft. In several navies throughout the world stepped-hull planing boats have been introduced in the littoral warfare communities with some apparent success.

John Zseleczky Behind The Scenes Of Peak Acceleration Measurements Most technical papers and reports on seakeeping tests for high speed vehicles skip over details of measurement and data processing for peak acceleration statistics. It is assumed that the reader is familiar with the methods used to obtain the test results and that all facilities make the measurements the same way. In the past few years there has been renewed interest in this area and several papers have been written on the subject (Coats, et al. 2007, Riley, et al. 2010 (a-c), 2011, Grimsley, et al. 2010, McCue et al. 2012). It is an exciting time in this field but the relatively small group of people who make the measurements and perform the analysis sometimes speak in their own language. Engineers tend to specialize in one area or another – hydrodynamics, structures, electronics, computer programming – and it may be difficult for any one person to follow all of the analysis issues discussed without a general understanding of concepts in each area. The intent of this paper is to flesh out some of the details that are usually not reported regarding what goes on before the final analysis and to provide an overview of how peak acceleration values are obtained. The information presented could be considered overly basic by electronics or computer experts however it may be of use to naval architects who are not in the field of testing but have a vested interest in the outcome of acceleration measurements. THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Abstracts

Michael R. Riley, Timothy W. Coats A Simplified Approach For Analyzing Rigid Body Accelerations Induced By Wave Impacts In High-Speed Planing Craft

This paper presents a simplified approach and interim criteria for computing the average of the 1/Nth highest accelerations when analyzing accelerometer data recorded during trials of manned and unmanned planing craft (on full scale or model scale) during rough water seakeeping trials. The computational approach and the interim criteria are based on analysis practices that have evolved over a number of years at the Combatant Craft Division of Naval Surface Warfare Center, Carderock Division as a set of best-practices for achieving repeatability when computations are performed by different data analysts. Fundamental characteristics of craft wave encounters are discussed, and interim criteria for the simplified computational approach are presented. Typical data recorded during full-scale trials of high-speed planing craft are presented to illustrate results of the computational approach. The paper also presents a process for representing mathematically the vertical acceleration response caused by a single wave impact, and presents examples of how the mathematical model can be used to estimate wave impact effects on craft.

Leigh McCue, Don Jacobson, Charles Weil, John Zseleczky A Look At The Impact Of Filter Selection On Peak Identification Of High Speed Craft Vertical Accelerations This study was motivated by the desire to rapidly identify Types Alpha, Bravo, and Charlie slam events as defined in Riley, et al., (2010a), in an automated manner. Riley, et al. observed particular characteristics of vertical acceleration in the wave slam response of high-speed craft. These characteristic acceleration responses were identified as Alpha, Bravo, and Charlie based on free fall acceleration and longitudinal acceleration peaks as described in (2010a). A numerical code was developed to identify Alpha, Bravo, and Charlie events by searching for free fall occurrences and longitudinal acceleration peaks during a slam event. The specific procedure is as follows; note steps 1-5 follow the “Standard g” approach (Riley, et al, 2010b).

Michael R. Riley, Timothy W. Coats A Method For Computing Wave-Impact Equivalent Static Accelerations For Use In Planing Craft Hull Design

Riders experience motions in six degrees of freedom including heave, surge, and sway plus the rotations about the three principle axes. The challenge for the developers of current craft hull design methods was to analyze these complicated motions to understand the fundamental cause and effect relationships between wave impact loads and craft response motions. They then had to synthesize lessons learned with simplifying assumptions to make tractable an otherwise seemingly unsolvable problem: what pressure values to use in design calculations to minimize the risk of structural damage. This paper summarizes recent developments that are generally applicable to planing craft that weigh up to approximately 46,000 pounds with overall lengths 55 feet or less. Typical average planing speeds for these craft can vary from 25 knots to 40 knots or more in head seas characterized by significant wave heights typically in the range of 2.0 feet to 5.5 feet. THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Abstracts

Eric Giesberg, Raju Datla Development Of Empirical Equations For Planing Craft Motions In Irregular Waves Through Genetic Algorithms An approximate and quick prediction of planing boat performance in irregular waves is useful for verifying concept designs and for seeing the effects of speed, wave height and various geometric parameters on motions. Simple, but fairly accurate for initial design, empirical equations currently only exist for estimating vertical accelerations and added resistance, but not for heave and pitch motions. The present paper studies the effect of planing boat geometry parameters, speed and wave height on the resulting motions and accelerations. A genetic algorithm, a regression method that mimics natural evolution to optimize a solution, was used to develop the empirical equations. Data sets were taken from prismatic model tests by Fridsma(1971) and Brown (1980); and a free software tool, Eureqa, was used to generate several equations for heave, pitch, accelerations at the center of gravity and bow. The equations were narrowed down by hand picking and looking at trend graphs, and the final equations were selected on the basis of simplicity, accuracy and physical correctness. The accuracy of the newly generated equation was then compared against the existing methods, Fridsma's charts for heave and pitch and Savitsky's empirical equations for accelerations. Additional validation was performed using model results from Coast Guard 47 ft. MLB standard series and a few other newer hull forms tested in the Davidson Laboratory.

Carolyn Q. Judge Static And Dynamic Forces And Wetted Lengths For A Planing Hull Model Forced In Roll

An experimental program at the United States Naval Academy has been designed to investigate the transverse plane stability of planing hulls. An experimental mechanism to force a planing hull model in roll motion was designed and built. The first model tested was a wooden prismatic planing hull with a constant deadrise of 20°, a beam of 1.48 ft (0.45 m), and a total length of 5 ft (1.52 m). The model was forced in roll while fixed in pitch, heave, sway, yaw and surge. The tests were done at three model speeds, two displacements, three roll amplitudes, and four oscillation frequencies. In addition to the dynamic tests, the model was run at the same model speeds and displacements while held fixed in roll at seven heel angles between 0° and 30°. For both the dynamic and static roll conditions the heave and sway forces, along with the roll moment, were measured and underwater photography was taken. This paper will explore how the heave and sway forces and roll moments depend on heel angle and roll amplitude as well as how the wetted lengths (keel and chine) vary between the static and the dynamic roll conditions.

Christopher S. Chaney, Konstantin I. Matveev Modeling Of Vertical-Plane Motions Of Tunnel Hulls

Tunnel hull boats, capable of achieving speeds up to 150 knots, are among the fastest waterborne vehicles. A tunnel hull configuration consists of a platform and two side hulls. The weight of this craft is supported mainly by hydrodynamic forces on the hulls and aerodynamic force on the platform. Utilization of aerodynamic support usually improves the boat’s lift-drag ratio. However, it also leads to deterioration of stability characteristics. Frequent crashes of high-speed boats, including tunnel hulls, show the importance of stability issues. In this study, a mathematical model is developed for vertical-plane motions of tunnel hulls. Nonlinear formulations of the added- mass strip theory and extreme ground effect theory account for unsteady hydrodynamic and quasi-steady aerodynamic forces, respectively. The influence of the system’s geometrical and loading parameters on transitions to unstable regimes is demonstrated. Simulations of unsteady motions, such as responses to wind gusts and behavior in waves, are also shown. The developed mathematical model can be applied for design of a variety of fast boats with aerodynamic support. THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Abstracts

Jeffrey Bowles Turning Characteristics And Capabilities Of High-Speed Mon hulls

The turning characteristics and capabilities of displacement vessels are well understood and documented. Standards for the maneuvering capability of displacement vessels exist. However, the same information regarding high speed craft is not so readily available. Most documents in the public domain contain information on what high speed craft shouldn’t be able to do, not what they should be able to do. This paper examines various aspects of the turning capabilities and characteristics of high speed monohull craft with regard to typical behavior and what type of maneuvering performance should be achievable. The dynamics, characteristics, and relationships of a hard chine monohull in a high speed turn are investigated and summarized. The execution of high speed turns on hard chine monohulls can sometimes lead to unexpected responses. This paper identifies several of the typical symptoms. The severity of these events will be discussed, and typical causes are identified. Notional maneuvering criteria are also proposed.

William Burns, T.J. Perrotti, Chris Todter, Daniel Casal, Johnny Smullen, John G. Hoyt III M Ship’s Rapid Empirical Innovation (Rei) Open Water Model Test Platform

M-Ship Co. has developed an innovative Rapid Empirical Innovation (REI) approach to open-water ship model testing with the goal of providing a system targeted towards rapid, low cost ship design. The system is designed to provide test data quality close to that of a towing tank, at a substantially lower cost. It is capable of both smooth water drag and trim measurement as well as rough water drag and motions assessment, comparable to towing tank measurements. After developing, testing, and refining the testing platform, and its systems, a series of arbitrary models (including the classic Series 62 model) of widely varying concepts were designed, produced, and tested using the REI system. This process consisted of an extensive set of smooth water, and rough water tests to characterize the models as well as the testing platform. The final phase of the program was validation, by taking three of the models (including the historically tested Series 62 model) to the NSWCCD David Taylor Model Basin (DTMB) for both smooth and rough water testing so comparisons could be made between the towing tank data (DTMB) and the REI system. All phases of platform development and data quality investigation were successfully completed in 2011. Our report will summarize M Ship’s testing methodology and comparative results.

Romain Garo, Raju Datla, Leonard Imas Numerical Simulation Of Planing Hull Hydrodynamics

Planing hull performance in calm water was modeled numerically using FineMarine, a finite volume-based Navier- Stokes solver with free-surface capturing algorithm and RANS turbulence model. The applied free-surface capturing method uses a compressive discretization scheme with interface reconstruction which permits for robust resolution of the density discontinuity between air and water thereby allowing for the study of spray break-up in the context of spray rail design and placement, for example, which is particularly relevant in planing hull hydrodynamics. A USCG 47 ft motor life boat design was used as the geometry in this study. The results were compared against 1/8th scale model test results, obtained from towing tank studies conducted on the same geometry at the Davidson Laboratory. A comparison of the wetted surface, resistance and running trim for four different loading configurations of the hull at three different speed-length-ratios between numerical simulations and model test results is shown. THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Abstracts

Thomas T. O’Shea, Kyle A. Brucker, Donald Wyatt, Douglas G. Dommermuth, Thomas C. Fu A Detailed Validation Of Numerical Flow Analysis (Nfa) To Predict The Hydrodynamics Of A Deep-V Planing Hull The focus of this paper is to describe and document the recent effort to validate the computer code Numerical Flow Analysis (NFA) for the prediction of hydrodynamic forces and moments associated with deep-V planing craft. This detailed validation effort was composed of three parts. The first part focuses on assessing NFA’s ability to predict pressures on the surface of a 10 degree deadrise wedge during impact with an undisturbed free surface. Detailed comparisons to pressure gauges are presented for two different drop heights, 6 inches and 10 inches. Results show NFA accurately predicted pressures during the slamming event. The second part examines NFA’s ability to match sinkage, trim and resistance from experiments performed on constant deadrise planing hulls, detailed in Fridsma (1969). Simulations were preformed on two 20 degree deadrise hullforms of varying length to beam ratios (4 and 5) over a range of speed-length ratios (2, 3, 4, 5, and 6 knots-ft -1/2). Results show good agreement with experimentally measured values, as well as values calculated using Savitsky’s parametric equations, detailed in Savistsky (1964). The final part of the validation study focused on assessing how well NFA was able to accurately model the complex multiphase flow associated with high Froude number flows, specifically the formation of the spray sheet. NFA simulations of a planing hull fixed at various angles of roll (0 degrees, 10 degrees, 20 degrees, and 30 degrees) were compared to experiments from Judge (2012). Comparisons to underwater photographs illustrate NFA’s ability to model the formation of the spray sheet and the free surface turbulence associated with planing boat hydrodynamics.

Frank DeBord, Karl Stambaugh, Chris Barry, Eric Schmid Evaluation Of High-Speed Craft Designs For Operations In Survival Conditions Designs for high-speed planing craft are typically driven by performance on plane in operating sea conditions. These conditions govern the principal characteristics, installed power, structural design and design features related to seakeeping and handling. When these high-speed craft are operated for military, law enforcement or search and rescue missions, performance and safety in severe seas at low speed can become issues and should be considered during design. This paper discusses the issues related to operations in these survival conditions and provides examples of performance analyses related to: (1) stability and flooding; (2) capsize, broaching and control problems; (3) structural design; and (4) seakeeping motions and acceleration affects on crew, machinery and systems. For each of these aspects of performance, analysis methodologies are discussed and typical results are provided. Methods for comparing risks associated with operations in various sea conditions are developed and recommendations are formulated for definition of limiting conditions. Finally, areas where typical design practices are found to be deficient related to these survival operations are identified and discussed.

Tony Caiazzo, Sid Charbonnet, Lou Codega Design, Construction And Testing Of The Advanced Composite Riverine Craft Seemann Composites, Inc. was awarded a series of contracts that allowed it to research, design, build and test a craft that virtually re-writes how riverine warfare craft are built. While the program was focused on this specific mission, the results of have wide reaching implications for all composite craft. The initial goal of the Advanced Composite Riverine Craft program was to develop a hull material and construction technique that would have the toughness and damage tolerance of conventional aluminum but would offer the advantages of significant weight reduction and elimination of the permanent deformation inherent in a metal structure. The team undertook an extensive analysis and materials test program to develop a bottom laminate specification to meet these goals. This laminate was incorporated into a hull bottom concept that was essentially unsupported by secondary structure. A craft was then designed around this bottom specification, with minimal artificial constraints placed on the design. The result was an innovative, fully operational 43 foot long fiber reinforced plastic craft that was powered by twin diesel engines and waterjets and had a top speed of over 45 knots. To conclude the program, the ACRC was impact tested to demonstrate that the original design goals of light structural weight and high damage tolerance were indeed met.

THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Abstracts

Albert Nazarov On Application Of Parametric Method For Design Of Planing Craft

Paper describes features of parametric method based on combined analysis of main dimensions and volumes, weight components, performance and range predictions, seakeeping and construction cost of planing craft. Method is derived from statistics of designs of special, pleasure and small commercial monohull craft with hull length below 30m, developed by Albatross Marine Design. Dimensions of hull are defined from usable areas and essential volumes, with recommendations provided for different architectural types of boats. Equations are proposed for weight groups based on hull dimensions, horsepower, type of propulsion system, level of accommodations and furnishing, required payload, etc. Approaches for preliminary estimate of powering, range, fuel efficiency, ride stability are provided. Method proved to be efficient tool for analysis, optimization and feasibility check of design requirements. Case studies are presented illustrating application of parametric approach for different designs.

Jan Alexander Keuning Improved design of a Search And Rescue boat for the Royal Netherlands Lifeboat Institution

The Royal Netherlands Sea Rescue Institution (KNRM) exploits a fleet of lifeboats around the North Sea coast of the Netherlands. The majority of this fleet consists nowadays of so called Rigid Inflatable Boats “RIB’s”. The largest vessels in the fleet are from the “Arie Visser” class, with a length of around 18.5 meters and a maximum speed of 35 knots. These are all weather boats on the North Sea and its coastal areas and self-righting. The Lifeboat Institution plans to replace the 10 boats in this class in the next 10 years. So an improved design (if possible) is sought for. A design group has been composed for this purpose consisting of the Shiphydromechanics Department of the Delft University of Technology, Design office W. de Vries Lentsch, (the designers of the existing boats) and the High Speed Craft Department of Damen . Based on the requirements of the Sea Rescue Institution (KNRM) the group developed two new designs. These designs were initially derived using computer simulations and calculations. The emphasis in these new designs was on improved operability of the Search and Rescue boats in their typical working environment and improved habitability (i.e. noise and vibrations). To assess the differences in performances of these designs in calm water and in waves an extensive test program has subsequently been set up and carried out with the three designs: i.e. the existing design Arie Visser and the two new designs. Extensive full scale measurements on the existing boats of the “Arie Visser” class had already been carried out in the past and these results were used to specify the behavior of the existing boats as a bench mark. Then the three designs, i.e. the Arie Visser, the Concept 1 and the Concept 2, have been tested for their resistance, sinkage and running trim in calm water. In addition their behavior with high forward speeds in head irregular waves have been tested with emphasis on measuring motions and vertical accelerations. Next their behavior in high stern quartering, following and beam seas has been investigated with free sailing models in the of MARIN to compare the new designs with the existing one for difference in a possible tendency for bow diving and broaching behavior in these high seas. In addition severe breaking waves have been simulated in the towing tank and the models run through these both in head as well as following waves conditions. The findings based on the computer simulations have been compared with the results from the measurements. The results of this research project will be summarized and presented in the present paper.

THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Abstracts

Christopher D. Barry Composite Techniques For Affordable Limited Production, Sustainable High Performance Yacht Construction; Not What You Might Think

One problem for high performance yachts is to produce a light enough, strong enough structure. This is possible with modern composite construction, but at substantial cost to produce the molds. Thus composites are difficult for limited or amateur construction. However, the term “composite” means a combination of any two different materials. Prior to advent of fiberglass, “composite construction” meant a combination of wood and metal, generally wood planks and perhaps primary framing over steel or aluminum secondary framing and other heavy structure. This type of composite construction enjoyed a limited short renaissance in the early 80’s (for high performance sailing yachts), due to the popularity and high performance potential of one-off cold molded wood construction. Simultaneously, it was hoped that CAD and CNC technology would help to revive wood boatbuilding. The wooden U.S. Navy MSH class in the 80’s implemented considerable CNC construction technology but much of the most involved labor on a wooden craft is on heavy internal structure which requires six axis cutting, with equipment too expensive for widespread use. Another issue is the difficulty of finding (or laminating) heavy timbers for main structural members such as keels. The combination of three axis CNC cutting and the use of metal for heavier structure offers solutions to these problems. The major framing is cut out of metal by plasma arc, water jet or laser cutters. The wood shell is made by strip planking, cold molding, or a combination; or lap strake planking, or most appropriate for planing craft, plywood. Especially in the last case, planks or shell “plating” can be CNC cut as well, providing substantial reductions in labor for a one-off or limited production boat compared to either making a mold for a fiberglass boat or for traditional wood construction. This technique is also amenable to sustainable wood resources, and of course, metals are generally from recycled sources and readily recyclable. This process also is easy for amateur builders because the metal and wood can be precut as a kit. This technique provides as good structural performance as any system except the most exotic cored carbon fiber or Kevlar systems at sizes from as small as six or seven meters to 30 meters or so, especially for hard chine, developable plywood hull forms. The paper examines the structural performance of composite construction; variations of this technique; optimization of structural performance by setting the wood/metal transition; materials, fasteners and adhesives; and specific details, tools and techniques for CAD , design and construction.

THE THIRD CHESAPEAKE POWERBOAT SYMPOSIUM June 15-16, 2012 St. John's College, Annapolis, Maryland, USA Acknowledgements

First the CPBS Committee would like to thank the Authors and Presenters. Without them there would be no Chesapeake Power Boat Symposium.

Next we would like to thank the Members and Staff of the Society Of Naval Architects And Marine Engineers, who have guided us, provided financial support when it was needed and have been publicizing the Symposium for us. These include:

Peter Noble, Alexander Landsburg, David Helgerson, Daniel Eling, William Peters, Christopher Barry, Karin Goodwin, Yenny Louie, Susan Evans Grove, Alana Anderson

The people at Professional Boat Builder, especially Mr. Carl Cramer who have supported and publicized the CPBS from the very beginning.

For Subsidizing the cost to our Student Participants we would like to thank CDI Marine, Band-Lavis Division especially:

David Lavis, Dan Bagnell

The Staff at St. Johns College who have now provided the facilities, meals and beverages including:

Diane Ensor, Kathleen Langman, and especially Sylvia Wilkerson who took care of feeding us

Our Biographer, Mr. Dean Schleicher, who prepared this years paper for our Honoree Donald Blount.

And finally, Bill Mish, someone who deserves all of our thanks for Chairmaning the first two CPBS's, who invested much time, effort and money into making the first two Symposiums such a success. His efforts went virtually unnoticed because he is an unassuming and humble man. Only those who have sat in his shoes understand the effort and sacrifices he made on our behave.

The 3rd Chesapeake Power Boat Symposium Committee

John G. Hoyt II, Chairman Edward M. Lewandowski, Papers Chairman Russell Krull, Treasurer Eric Greene, Web Master, Publicity Christopher Bassler, SNAME Liaison Raju Datla, Member Martin Dipper, Member John Zseleczky, Member