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April 2013 www.sname.org/sname/mt ( abstracts )SNAME Paper Abstracts Sail Aerodynamics: On-Water Pressure Measurements on a Downwind Sail BY IGNAZIO MARIA VIOLA AND RICHARD G. J. FLAY PUBLISHED IN THE DECEMBER JOURNAL OF SHIP RESEARCHPressures on three horizontal sections of a downwind sail were measured for several wind directions and sail trims. e pressure distributions were compared with wind tun- nel tests; similarities and dierences were found, the latter as a result of the dynamic eects, which were not modeled in the wind tunnel. A pressure distribution at the head of the spinnaker resembling that from a delta wing was measured at an apparent wind angle of 120°.A Wave Resistance Formulation for Slender Bodies at Moderate to High Speeds BY BRANDON M. TARAVELLA AND WILLIAM S. VORUS PUBLISHED IN THE DECEMBER JOURNAL OF SHIP RESEARCHT. Francis Ogilvie (1972) developed a Greens function method for calculating the wave prole of slender ships with ne bows. He rec- ognized that near a slender ships bow, rates of change of ow variables axially should be greater than those typically assumed in slender body theory. Ogilvies result is still a slen- der body theory in that the rates of change in the near eld are dierent transversely (a half-order different) than axially; however, the dierence in order of magnitude between them is less than in the usual slender body theory. Typical of slender body theory, this formulation results in a downstream stepping solution (along the ships length) in which downstream eects are not reected upstream. Ogilvie, however, developed a solution only for wedge-shaped bodies. Taravella, Vorus, and Givan (2010) developed a general solution to Ogilvies formulation for arbitrary slen- der ships. In this article, the general solution has been expanded for use on moderate- to high-speed ships. e wake trench has been accounted for. e results for wave resistance have been calculated and are compared with previously-published model test data. Generalized Modes in Time-Domain Seakeeping Calculations BY JOHAN T. TUITMAN, SIME MALENICA, AND RIAAN VAN T VEER PUBLISHED IN THE DECEMBER JOURNAL OF SHIP RESEARCHThe concept of generalized modes? is to describe all degrees of freedom by mode shapes and not using any predened shape, like rigid body modes. Generalized modes in seakeeping computations allow one to calcu- late the response of a single ship, springing, whipping, multibody interaction, etc., using a uniform approach. e generalized modes have already been used for frequency-domain seakeeping calculations by various authors. is article extends the generalized modes methodology to be used for time-domain seakeeping computations, which accounts for large-amplitude motions of the rigid-body modes. e time domain can be desirable for seakeeping computations because it is easy to include nonlinear load components and to compute transient response, like slamming and whipping. Results of multibody inter- action, two barges connected by a hinge, whipping response of a ferry resulting from slamming loads, and the response of a exible barge are presented to illustrate the theory. System Reliability of Ship Hull Structures Under Corrosion and Fatigue BY KIHYON KWON AND DAN M. FRANGOPOL PUBLISHED IN THE DECEMBER JOURNAL OF SHIP RESEARCHSystem reliability of ship hull girder struc- tures is evaluated considering uncertainties in ultimate bending capacity and sea loads. Lifetime structural deterioration models are developed at the system level. Time-variant random functions associated with corrosion and fatigue cracking are formulated to estimate the ultimate bending moment capacity. Still water and wave-induced bending moments are computed by using design-oriented and simplified direct methods. For sagging and hogging moments, structural performance in the intact hull condition is investigated con- sidering dierent sea states as well as dierent ship operating speeds. e approach proposed is illustrated on a ship hull girder structure. Probabilistic Fire Safety Assessment of Passenger Ships BY NIKOS THEMELIS AND KOSTAS J. SPYROU PUBLISHED IN THE DECEMBER JOURNAL OF SHIP RESEARCHA probabilistic framework is proposed for the assessment of passenger ship re safety that is based on a structured generation of design res.? e aim is to establish a ratio- nal and practical means for evaluating design selections (materials, geometry, sensors, and suppressors) that inuence re safety with reference to the implicit safety objectives attended by the current regulations. Thus, alternative design solutions could be eval- uated more comprehensively. Fire growth Editors note: The following are abstracts of papers recently presented at SNAME events and/or published in SNAME publications. The paper s can be found at www.sname.org/ sname/mt/featuredabstracts View current and previous issues of Journal of Ship Production and Design and Journal of Ship Research at http://www.sname.org/SNAME/Pubs/Journals1/