Small Waterplane Area Ships

V. Dubrovsky K. Matveev S. Sutulo

isbn-13: 978-09742019-3-1 US$149 :: Hardbound 255 pages :: 7.5"x10" :: © 2007

Started as experiments a few decades ago, SWATH vessels have already proved their superiority in certain applications in which their excellent seaworthiness coupled with high deck area to displacement ratio are of primary importance. With their smooth ride and little if any loss of speed on rough seas they provide comfortable, fast and timely ferry service, reliable patrol and rescue services, and a stable platform for all-weather helicopter take-off and landing. The logic of utilizing the inherent advantages of small waterplane area hulls has led naval architects and designers to apply this feature to various multi-hull arrangements, thus combining the benefits of different types of ships into a single vessel. This is exactly the focus of the present book which provides the wealth of the existing experimental and theoretical results (with signifacant contributions by the authors) and their application for designing new high-performance vessels. Small waterplane area (SWA) ships, like other multi-hull ships, are relatively novel in the marine industry. Statistical databases and practical experience for designing these ships are sporadic and spread in scattered publications. The book presents the basic information required for designing the SWA ships encompassing the first principles and a bulk of necessary databases both developed by the authors and available in the public domain, collected under a single cover. The book contains seven chapters and ten appendices.

Ch. 1. Introduction explains how small waterplane area, which is the main feature of SWA ships, and the division of buoyancy into several hulls, as in all multi-hull ships, makes the SWA ships superior for sailing in rough seas and convenient for passenger and light-weight cargo transportation.

Ch. 2. General Geometry and Hydrostatics shows how these features provide plenty opportunities for designing vessels with unique combinations of performance characteristics unimaginable for traditional monohulls.

Ch. 3. Resistance and Propulsion in Still Water analyzes the data of the biggest currently published series of SWA model tests (more than 300 variants of shapes and arrangements of hulls). Recommendations are given for selecting the types of SWA ships most appropriate for particular operations. Ch.3 is supported by Appendices A - D presenting the experimentally based data on interaction between hulls for SWATH and tri-hull vessels with different arrangements and sizes of hulls, Appendix E on wave systems generated by SWATH vessels, Appendix G on dynamic unloading and foil design, Appendix H on recent advances in the use of air cavities for reducing the viscous resistance of SWATH vessels, and Appendix J on towing resistance of semi-submersible rigs.

Ch. 4. Seakeeping and Loss of Speed in Waves presents an analysis of SWATH behavior and recommends operational tactics in rough seas, as well as the methods of using active foils and air-activated tanks for mitigating the ship motions. A concise review of feedback control laws is given as well as the basic principles and approaches to design and analysis of control systems. Appendix F presents a summary of the seakeeping standards proposed by different authors.

Ch. 5. Notes on SWATH Maneuverability presents a discussion of dynamic characteristics and controllability of SWATH and their dynamic attitude and motion stability with practical recommendations for design of controlling surfaces. Appendix I presents mathematical modeling of the SWATH maneuvering motion and stabilizing fins.

Ch. 6. Loads and Structural Design analyzes the global and local strength of SWATH with an emphasis on the transverse strength. A new concept is introduced for the platform-strut connection that allows one to save weight and reduce impact loads on the platform.

Ch. 7. Comments on Design presents a general SWATH design algorithm based on a deck capacity equation with several iterations and parametric variations. A number of examples are given demonstrating the potentials of SWA vessels for fast and all-weather passenger and cargo transportation and support services. References contain a bulk of related literature in the public domain. Glossary, Acronyms, Nomenclature, and Subject Index are provided for the reader's convenience.

This book is a continuation of the monograph Multi-Hull Ships by Dubrovsky & Lyakhovitsky providing new and significantly extended knowledge for practical design and demonstrating great potentials for future applications of SWA ships. Like the mentioned monograph, this book is addressed to naval architects, designers, researchers, professors, graduate and senior undergraduate students, managers and other involved in design, research, rule development, plan approval, acquisition, planning and operation of small waterplane area vessels. The book is written by three authors representing three generations of Russian naval architects. The lead author, Victor Dubrovsky, from the first days of his career has been immersed into hydrodynamic research and design of multi-hull vessels including those with small waterplane area. This was at a time when the word catamaran was known, mainly as a Polynesian boat, to curious minds only and long before the acronym SWATH was created. For English-speaking readers he is known for the recently published fundamental monograph Multi-Hull Ships (co-authored by A. Lyakhovitsky) and Ships with Outriggers. The youngest of the authors, Konstantin Matveev was fortunate to start his career at the very heart of the innovation design center which at that time was the undisputed USSR leader in hydrofoils and the world only builder of the pioneering WIG craft. With the experience he gained there and an appetite for innovation, he continued his career in a number of the finest design and research centers in the USA. The significant contributions made by Serge Sutulo have been focused on maneuverability and seakeeping of surface displacement ships and other marine vehicles. Carried in several countries and published in four languages, his works combine detailed theoretical research with experimental studies in one of the most complicated fields of the ship hydrodynamics.