METACENTRIC HEIGHT of a CATAMARAN 164 40 Metacentric Height of a Catamaran
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On the Great Trimaran-Catamaran Debate
On the Great Trimaran-Catamaran Debate Lawrence J. Doctors, Member, School of MechanicnJ and Manufacturing Engineering, The University of New South Wales, Sydney, NSW 2052, Australia Abdmct In the cumwtt work, a aydewaatic investigation into a variety of monohulls and mul- tihulls is carried out with an emphasis on finding optimal forms. Vessels with up to six identical subhulls are taken into consideration and a large range of lengths is studied. hT- thermore, sidehuli trimaran configurations are included in the investigation. There are two main purposes to this investigation. Firstly, one is interested in mini- mizing the wave resistance, becawe this is closely related to the wave generation and is of critical importance to the operation of river ferries. Secondly, it is also important to min- imize the total resistance, in order to reduce fuei costs and to permit long-range trips for ocean-going vessels. The theoretical predictions show that increasing the length beyond that normally accepted is beneficial in reducing both the wave Resistance and often the total resistance. I. the goal is to minimize wave resistance and if the length is constrained, the calculations also demon- strate that trimarans are superior to catamarans, which are in turn superior to monohulls. On the other hand, if the goal is to minimize the total resistance, then all the muh!ihulis (~m catamarans to hezamarans) are inferior to monohulls, except possibly at low speeds which are not of interest in thw study. Similarly, sidehull trimarans are shown to be inferior to catamarans except perhaps if rather great lengths are permitted. -
Trimarans and Outriggers
TRIMARANS AND OUTRIGGERS Arthur Fiver's 12' fibreglass Trimaran with solid plastic foam floats CONTENTS 1. Catamarans and Trimarans 5. A Hull Design 2. The ROCKET Trimaran. 6. Micronesian Canoes. 3. JEHU, 1957 7. A Polynesian Canoe. 4. Trimaran design. 8. Letters. PRICE 75 cents PRICE 5 / - Amateur Yacht Research Society BCM AYRS London WCIN 3XX UK www.ayrs.org office(S)ayrs .org Contact details 2012 The Amateur Yacht Research Society {Founded June, 1955) PRESIDENTS BRITISH : AMERICAN : Lord Brabazon of Tara, Walter Bloemhard. G.B.E., M.C, P.C. VICE-PRESIDENTS BRITISH : AMERICAN : Dr. C. N. Davies, D.sc. John L. Kerby. Austin Farrar, M.I.N.A. E. J. Manners. COMMITTEE BRITISH : Owen Dumpleton, Mrs. Ruth Evans, Ken Pearce, Roland Proul. SECRETARY-TREASURERS BRITISH : AMERICAN : Tom Herbert, Robert Harris, 25, Oakwood Gardens, 9, Floyd Place, Seven Kings, Great Neck, Essex. L.I., N.Y. NEW ZEALAND : Charles Satterthwaite, M.O.W., Hydro-Design, Museum Street, Wellington. EDITORS BRITISH : AMERICAN : John Morwood, Walter Bloemhard "Woodacres," 8, Hick's Lane, Hythe, Kent. Great Neck, L.I. PUBLISHER John Morwood, "Woodacres," Hythc, Kent. 3 > EDITORIAL December, 1957. This publication is called TRIMARANS as a tribute to Victor Tchetchet, the Commodore of the International MultihuU Boat Racing Association who really was the person to introduce this kind of craft to Western peoples. The subtitle OUTRIGGERS is to include the ddlightful little Micronesian canoe made by A. E. Bierberg in Denmark and a modern Polynesian canoe from Rarotonga which is included so that the type will not be forgotten. The main article is written by Walter Bloemhard, the President of the American A.Y.R.S. -
5 Must Read Sailing Books for Catamaran Enthusiasts
5 Must Read Sailing Books for Catamaran Enthusiasts This list briefly discusses 5 books that yacht owners or enthusiasts should read. What makes each book unique? Why should they read the book? What will they learn or take away from it? This is - at least what we consider - the best 5 books ever written in English on the subject of cruising catamarans. There are a few German and French publications but they are nearly impossible to get , most are out of print and unless you can read German or French - are of no value. So here is the top 5 list of the "Must Read books for Catamaran Enthusiasts" 1.) CATAMARANS - THE COMPLETE GUIDE FOR CRUISING SAILORS, by Gregor Tarjan. First published in 2006 and reprinted in 2008 by Mc Graw Hill Companies, New York. ISBN 9780071498852. Hardcover, 305 pages full color, large format, illustrated and lavish photography by Gilles Martin Raget. Of course we have to mention this book first. Not only is it written by our own Gregor Tarjan, founder and owner of Aeroyacht Ltd., but it is hailed as "the industry reference" by many experts. It has sold many thousands of copies around the world and has been re-printed numerous times. Jim Brown calls it "an authoritative guide for novices and experienced sailors, the best book written on the subject since the early 1990's" 2.) MULTIHULL SEAMANSHIP - Illustrated, by Dr. Gavin LeSueur. Illustrations by Nigel Allison. First published in Australia in 1995, Cyclone Publishers. ISBN 1875181032. Soft cover, spiral bound, large format, 108 pages, black and white. -
Senate 'Junk Mail' Costs to Be Disclosed That Ended Sept
Metuchen downs Keyport for title, IB MOSTLY CLOUDY Sodal Security Mostly cloudy today through tomorrow. Highs Game will range from 40 to 45 6B both days. The Register Complete forecast 2A. Vol. 108 No. 92 YOUR HOMETOWN NEWSPAPER...SINCE 1878 MONDAY, DECEMBER 9, 1985 25 CENTS MONDAY Foes seek to halt LOCAL Tinkering pays off Retired inventor's work in electronics plan for high-rise has gained several patents. Now he has a new one for a device that will would be expanded. Each is privately help electronics students. l| BOB NOT owned. The Register The 20-story, 168-unit hotel-condominium HIGHLANDS - Believing the character has been proposed perpendicular to Sandy STATE and ecology of the eastern Bayshore are in Hook Bay. straddling the Atlantic High- jeopardy, opponents of a proposed 20-story lands-Highlands border. Outnumbered hotel-condominium on the Atlantic High- Critics of the proposal, which has become Private treatment centers for lands-Highlands border said yesterday they a sensitive political issue, have become intend to defeat the proposal more vocal in recent months as residents emotionally disturbed Immediately affected oy construction of have become more aware of the two- teen-agers are not prepared to cope the waterfront high-rise and the accompany- borough project. with the growing number of ing proposed townhouses would be a 57-unit Gov. Thomas H. Kean and Rep. James J. youngsters transferred there from mobile home park and area wetlands. But Howard, p-N.J., each have written local New Jersey's overcrowded critics fear its Impact could be far-reaching. -
ORC Special Regulations Mo3 with Life Raft
ISAF OFFSHORE SPECIAL REGULATIONS Including US Sailing Prescriptions www.ussailing.org Extract for Race Category 4 Multihulls JANUARY 2014 - DECEMBER 2015 © ORC Ltd. 2002, all amendments from 2003 © International Sailing Federation, (IOM) Ltd. Version 1-3 2014 Because this is an extract not all paragraph numbers will be present RED TYPE/SIDE BAR indicates a significant change in 2014 US Sailing extract files are available for individual categories and boat types (monohulls and multihulls) at: http://www.ussailing.org/racing/offshore-big-boats/big-boat-safety-at-sea/special- regulations/extracts US Sailing prescriptions are printed in bold, italic letters Guidance notes and recommendations are in italics The use of the masculine gender shall be taken to mean either gender SECTION 1 - FUNDAMENTAL AND DEFINITIONS 1.01 Purpose and Use 1.01.1 It is the purpose of these Special Regulations to establish uniform ** minimum equipment, accommodation and training standards for monohull and multihull yachts racing offshore. A Proa is excluded from these regulations. 1.01.2 These Special Regulations do not replace, but rather supplement, the ** requirements of governmental authority, the Racing Rules and the rules of Class Associations and Rating Systems. The attention of persons in charge is called to restrictions in the Rules on the location and movement of equipment. 1.01.3 These Special Regulations, adopted internationally, are strongly ** recommended for use by all organizers of offshore races. Race Committees may select the category deemed most suitable for the type of race to be sailed. 1.02 Responsibility of Person in Charge 1.02.1 The safety of a yacht and her crew is the sole and inescapable ** responsibility of the person in charge who must do his best to ensure that the yacht is fully found, thoroughly seaworthy and manned by an experienced crew who have undergone appropriate training and are physically fit to face bad weather. -
Stability Analysis Based on Theoretical Data and Inclining Test Results for a 1200 GT Coaster Vessel
Proceeding of Marine Safety and Maritime Installation (MSMI 2018) Stability Analysis Based on Theoretical Data and Inclining Test Results for a 1200 GT Coaster Vessel Siti Rahayuningsih1,a,*, Eko B. Djatmiko1,b, Joswan J. Soedjono 1,c and Setyo Nugroho 2,d 1 Departement of Ocean Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia 2 Department of Marine Transportation Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia a. [email protected] *corresponding author Keywords: coaster vessel, final stability, preliminary stability. Abstract: 1200 GT Coaster Vessel is designed to mobilize the flow of goods and passengers in order to implement the Indonesian Sea Toll Program. This vessel is necessary to be analysed its stability to ensure the safety while in operation. The stability is analysed, firstly by theoretical approach (preliminary stability) and secondly, based on inclining test data to derive the final stability. The preliminary stability is analysed for the estimated LWT of 741.20 tons with LCG 23.797 m from AP and VCG 4.88 m above the keel. On the other hand, the inclining test results present the LWT of 831.90 tons with LCG 26.331 m from AP and VCG 4.513 m above the keel. Stability analysis on for both data is performed by considering the standard reference of IMO Instruments Resolution A. 749 (18) Amended by MSC.75 (69) Static stability, as well as guidance from Indonesian Bureau of Classification (BKI). Results of the analysis indicate that the ship meets the stability criteria from IMO and BKI. However results of preliminary stability analysis and final stability analysis exhibit a difference in the range 0.55% to 11.36%. -
A Comparative Evaluation of a Hydrofoil-Assisted Trimaran
COMPARATIVE EVALUATION OF A A HYDROFOIL-ASSISTED TRIMARAN Thesis presented in partial fulfillment of the requirements for the degree MASTER OF SCIENCE IN ENGINEERING By Ryno Moolman Supervisor Prof. T.M. Harms Department of Mechanical Engineering University of Stellenbosch Co-supervisor Dr. G. Migeotte CAE Marine December 2005 Declaration I, the undersigned, declare that the work contained in this thesis is my own original work and has not previously, in its entirety or in part, been submitted at any University for a degree. Signature of Candidate Date i Abstract This work is concerned with the design and hydrodynamic aspects of a hydrofoil-assisted trimaran. A design and configuration of a trimaran is evaluated and the performance of a hydrofoil-assisted trimaran is effectively compared to the performance of a hydrofoil-assisted catamaran with similar overall displacement and same speed. The performance of the trimaran with different outrigger clearances are also evaluated and compared. The hydrodynamic aspects focuses mainly on the performance and to a lesser extend on the sea-keeping and stability of a hydrofoil-assisted trimaran. The results were determined by means of experimental testing, theoretical analysis and numerical analysis. The project was initiated as a result of the success of the hydrofoil-assisted catamarans and due to the fact that there does not exist a hydrofoil-assisted trimaran (to the author’s knowledge) where the main focus of the foils is to significantly reduce the resistance. A brief history, recent developments and associated advantages regarding trimarans are discussed. A complete theoretical model is presented to evaluate the lift and drag of the hydrofoils, as well as, the resistance of the trimaran. -
The Practical Design of Advanced Marine Vehicles
The Practical Design of Advanced Marine Vehicles By: Chris B. McKesson, PE School of Naval Architecture and Marine Engineering College of Engineering University of New Orleans 2009 Version: Fall 2009 rev 0 This work sponsored by: US Office of Naval Research Grant No: N00014‐09‐1‐0145 1 2 CONTENTS 1 Summary & Purpose of this Textbook ................................................................................................ 27 1.1 Relationship of the Course to Program Outcomes ..................................................................... 28 1.2 Prerequisites ............................................................................................................................... 28 1.3 Resources .................................................................................................................................... 28 1.3.1 Numbered references cited in the text ................................................................................. 29 1.3.2 Important references not explicitly cited in the text ............................................................ 31 1.3.3 AMV Web Resources ............................................................................................................. 32 1.3.4 AMV Design Agents ............................................................................................................... 32 1.3.5 AMV Builders ......................................................................................................................... 33 2 A Note on Conventions ...................................................................................................................... -
Dictionary.Pdf
THE SEAFARER’S WORD A Maritime Dictionary A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Ranger Hope © 2007- All rights reserved A ● ▬ A: Code flag; Diver below, keep well clear at slow speed. Aa.: Always afloat. Aaaa.: Always accessible - always afloat. A flag + three Code flags; Azimuth or bearing. numerals: Aback: When a wind hits the front of the sails forcing the vessel astern. Abaft: Toward the stern. Abaft of the beam: Bearings over the beam to the stern, the ships after sections. Abandon: To jettison cargo. Abandon ship: To forsake a vessel in favour of the life rafts, life boats. Abate: Diminish, stop. Able bodied seaman: Certificated and experienced seaman, called an AB. Abeam: On the side of the vessel, amidships or at right angles. Aboard: Within or on the vessel. About, go: To manoeuvre to the opposite sailing tack. Above board: Genuine. Able bodied seaman: Advanced deckhand ranked above ordinary seaman. Abreast: Alongside. Side by side Abrid: A plate reinforcing the top of a drilled hole that accepts a pintle. Abrolhos: A violent wind blowing off the South East Brazilian coast between May and August. A.B.S.: American Bureau of Shipping classification society. Able bodied seaman Absorption: The dissipation of energy in the medium through which the energy passes, which is one cause of radio wave attenuation. Abt.: About Abyss: A deep chasm. Abyssal, abysmal: The greatest depth of the ocean Abyssal gap: A narrow break in a sea floor rise or between two abyssal plains. -
James Wharram and Hanneke Boon
68 James Wharram and Hanneke Boon 11 The Pacific migrations by Canoe Form Craft James Wharram and Hanneke Boon The Pacific Migrations the canoe form, which the Polynesians developed into It is now generally agreed that the Pacific Ocean islands superb ocean-voyaging craft began to be populated from a time well before the end of The Pacific double ended canoe is thought to have the last Ice Age by people, using small ocean-going craft, developed out of two ancient watercraft, the canoe and originating in the area now called Indonesia and the the raft, these combined produce a craft that has the Philippines It is speculated that the craft they used were minimum drag of a canoe hull and maximum stability of based on either a raft or canoe form, or a combination of a raft (Fig 111) the two The homo-sapiens settlement of Australia and As the prevailing winds and currents in the Pacific New Guinea shows that people must have been using come from the east these migratory voyages were made water craft in this area as early as 6040,000 years ago against the prevailing winds and currents More logical The larger Melanesian islands were settled around 30,000 than one would at first think, as it means one can always years ago (Emory 1974; Finney 1979; Irwin 1992) sail home easily when no land is found, but it does require The final long distance migratory voyages into the craft capable of sailing to windward Central Pacific, which covers half the worlds surface, began from Samoa/Tonga about 3,000 years ago by the The Migration dilemma migratory group -
Lalåyak – a Beginner's Guide to Sailing a Chamorro Canoe
LALÅYAK A Beginner’s Guide to Sailing a Chamorro Canoe © 2019 500 Sails. All rights reserved. This project was made possible by support from the Northern Marianas Humanities Council, a non-profit, private corporation funded in part by the National Endowment for the Humanities. Any views, findings, conclusions or recommendations expressed in this publication do not necessarily represent those of the National Endowment for the Humanities. The Northern Marianas Humanities Council will have non-exclusive, nontransferable, irrevocable, royalty-free license to exercise all the exclusive rights provided by copyright. Cover photo: Jack Doyle Pictured left to right: Cecilio Raiukiulipiy, Ivan Ilmova, Pete Perez (close canoe); Sophia Perez, Arthur De Oro, Vickson Yalisman (far canoe) Sail between Saipan and Tinian in Tinian Channel. Aguiguan Island in background. Table of Contents Preface .......................................................................................................................................................... 1 Introduction .................................................................................................................................................. 2 Historic Context ............................................................................................................................................ 2 Sakman Design .............................................................................................................................................. 4 Sailing Vocabulary ........................................................................................................................................ -
13.012 Hydrodynamics for Ocean Engineers Reading #3
13.012 Hydrodynamics for Ocean Engineers Reading #3 13.012 Hydrodynamics for Ocean Engineers Prof. A.H. Techet Fall 2004 Archimedes’s Principle and Static Stability “Any object, wholly or partly immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object.” “The apparent loss in weight of a body immersed in a fluid is equal to the weight of the displaced fluid.” I. Archimedes’s Principle: The force on a body due to pressure alone (in the absence of viscous forces) K F = ∫∫ p nˆ ds (3.1) S where pressure is a function of depth below the free surface: p(z) = −ρgz . (3.2) K F = ∫∫ p nˆ ds = − ρg ∫∫ z nˆ ds (3.3) S S By Calculus the surface integral can be converted into a volume integral (Gauss’s Theorem/Divergence Theorem): K K ∫∫G ⋅ nˆ ds = ∫∫∫∇ ⋅G dV (3.4) SV Thus equation becomes: K FpndsgzndsgdVgVk==−=∫∫ˆˆρρρ ∫∫ ∫∫∫ =ˆ (3.5) SSV version 3.0 updated 9/8/2004 -1- ©2003, 2004 aht 13.012 Hydrodynamics for Ocean Engineers Reading #3 We can see now that the buoyancy force acts to counterbalance the displaced volume of fluid. For a half submerged body the area of the water plane must be accounted for in the integration. II. Moment on a body (Ideal Fluid) The moment on a submerged body follows directly from structural mechanics or dynamics methodologies. K K M = p(x × nˆ) ds ≡ (M ,M ,M ) = (M ,M ,M ) (3.6) ∫∫ 1 2 3 x y z S Figure 1: x, y, z coordinate reference frame.