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July 2013 www.sname.org/sname/mt (abstracts) GO DEEPER Both the Journal of Ship Production and Design and the Journal of Ship Research are available by subscription. Go to www.sname.org/SNAME/Pubs/Journals1/ and ?nd out why these technical journals are indispensable to naval architects and marine engineers around the world. Volvo Open 70 yachts. Discussion of the logistical complexities involved in build- ing the eet of boats in the required time also is discussed. A review of the structural design is included to illustrate the eorts to improve construction eciency, reduce cost, and dramatically improve robustness of the yacht structures while minimizing the weight additions that result. Finally, we review some of the extensive quality control procedures and manufacturing technol- ogy that has been employed in an eort to achieve a eet of one-design yachts that are as identical to one another as possible. A Wind Tunnel Study of the Interaction Between Two Sailing Yachts BY P.J. RICHARDS, D.J. LE PELLEY, D. JOWETT, J. LITTLE, AND O. DETLEFSEN PUBLISHED IN THE CHESAPEAKE SAILING YACHT SYMPOSIUM PROCEEDINGS e interference between two yachts sail- ing in several conditions is investigated in the wind tunnel by using two similar yacht models, one of which is mounted on a force balance and the other moved around the test section. e yachts were congured to sail close-hauled upwind at 20° apparent wind angle, downwind under asymmet- ric spinnaker at 60°, and downwind under symmetric spinnaker at 120° apparent wind angle. The regions of positive and nega- tive interference are determined through aerodynamic force measurement and ow disturbance measurement, and the sources of these eects investigated. The Evolution of Design: SALTS New Sail Training Schooner Project BY S. DUFF, F. FOSSATI, ANDY CLAUGHTON, W. KRZYMOWSKI, AND TONY ANDERSON PUBLISHED IN THE CHESAPEAKE SAILING YACHT SYMPOSIUM PROCEEDINGS e Sail and Life Training Society is build- ing a new purpose-designed 35 m wooden sail-training schooner for unrestricted for- eign-going operations. Working with an international team of consultants, SALTS has initiated an ambitious agenda of ana- lytical and experimental investigations to support design, including a parametric study of hull form as it relates to stability at high angles of heel; the development of bespoke parametric design and anal- ysis tools using the graphical algorithm editor Grasshopper; a towing tank cam- paign at the Wolfson Unit to investigate the behavior of three keel proles; and a wind tunnel campaign at Politecnico di Milano to investigate the behavior of 15 sail plans. Preliminary results from these studies will be presented, set in the con- text of the unfolding story of the evolution of the design of the new vessel. Uniform-Panel Weld Shrinkage Data Model for Neat Construction Ship Design Engineering BY YU PING YANG, HARVEY CASTNER, RANDY DULL, JAMES R. DYDO, AND DENNIS FANGUY PUBLISHED IN THE FEBRUARY JOURNAL OF SHIP PRODUCTION AND DESIGN A weld shrinkage prediction model was developed for thin uniform ship panels to predict in-plane shrinkage. The weld shrinkage prediction model consists of a series of empirical equations developed by analysis of shrinkage data from welded panels fabricated in the shipyards. ese panels ranged in thickness from 3 mm to 9.5 mm and were welded with processes including submerged arc, ux cored arc, and gas metal arc welding. All fabrication data were carefully recorded using practices that were common over each of the ship- yards. Measurements of the panels were made throughout each step of fabrication to provide accurate weld shrinkage data. e data were then analyzed by regression analysis to produce equations that permit the calculation of weld shrinkage based on the conditions used for fabrication. ese shrinkage model equations were embed- ded in a Microsoft Excel spreadsheet for ease of use. Estimation of Resistance and Self- Propulsion Characteristics for Low L/B Twin-Skeg Container Ship by a High-Fidelity RANS Solver BY NOBUAKI SAKAMOTO, YASUTAKA KAWANAMI, SHOTARO UTO AND NORIYUKI SASAKI PUBLISHED IN THE MARCH JOURNAL OF SHIP RESEARCHReynolds-averaged Navier-Stokes sim- ulations, together with verication and validation studies for a low L/B twin-skeg container ship, are carried out using SURF version 6.44. is is a high-delity RANS solver for ship hydrodynamics devel- oped at the National Maritime Research Institute: single-phase level set free sur- face, Spalart-Allmaras/k- turbulence, and body-force propeller models; nite volume discretization; and parallelized by openMP for high-performance computing. At the beginning, simulat ion numerical uncertainty has been quantied for resis- tance and self-propulsion coefficients on the basis of the standard V&V proce- dure recommended by the International Towing Tank Conference. en the resis- tance and self-propulsion simulations are carried out at several speeds rang- ing from low to medium Froude numbers. The overall results are encouraging in that the solver accurately predicts resis- tance and self-propulsion coecients as well as velocity distribution at the propel- ler plane in comparison to the available experimental data. Further sophistica- tions in computational method, especially in estimating self-propulsion coecients, will lead the solver to be a more practical and powerful design tool. MT