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www.sname.org/sname/mt July 2013 severity comparison plots and computed values of RSI are presented to illustrate the simplicity of the approach and to demon- strate the ability to quantify what heretofore has relied primarily on the subjective expe- rience of operators. Uncertainties in the Wind-Heel Analysis of Traditional Sailing Vessels: The Challenges it Presents for Forensic Analysis of Sailing Incidents BY B. JOHNSON, W. LASHER, M. ERDMAN, JAN MILES, AND B. CURR PUBLISHED IN THE CHESAPEAKE SAILING YACHT SYMPOSIUM PROCEEDINGS ere are many uncertainties in the inter- pretation of full-scale sailing vessel data taken under dynamic conditions, and even more uncertainties when forensic analysis is attempted based only on survivors rec- ollections. Frequently, the analysis is based on static equilibrium assumptions, some- times modied to steady-state motions of the wind and heeling response of the vessel. Dynamic conditions are generally non- deterministic and statistical methods must be used. Even more complicated is the non- stationary random process nature of most accidents. In the wind-heel research car- ried out on Pride II , it has been shown that wave action frequently adds uncertainty to the correct attribution of contributions to establishing the cause of resulting heeling action. e best data are found in steady 10 to 20 knot wind strengths in minimum waves found in the lee of a shoreline. is criteria can be interpreted as minimiz- ing the uncertainties in characterizing the wind-heel performance of a given sail com- bination at normal angles of heel. Examples of quasi steady-state response are presented in the paper as characterized by the wind heel stiness ratio (WHSR), which is equal to the square of the apparent wind veloc- ity in knots divided by the resulting heel angle in degrees. WHSR is not non-dimen- sional but is independent of the system of units, (SI vs. EG). e WHSR for each sail combination is most easily established by a maneuver the crew of Pride II has deemed the crazy Ivan.? However, it is uncertain whether this concept can make useful pre- dictions at heel angles higher than those beyond GZmax in the absence of any good data taken during these conditions. CFD studies of various sail combinations pro- vide very good agreement between the recorded wind-heels responses of the ves- sel up to deck edge submergence. The corresponding CFD predictions provide a method of predicting the normal wind heel responses of a traditional sailing vessel during the design process. e paper dis- cusses operational guidance uncertainties that appear as a fork in the road? decision, with bearing away as one path and head- ing up as the other. The paper examines the tradeos in the decision making pro- cess relative to the type of vessel involved and the observable wind and sea conditions at the time. Recent attempts to re-analyze the dismasting of Pride II in 2005 and the sinking of Concordia o Brazil in 2010 also are included. Development of Volvo Ocean 65 BY BRITTON WARD AND CHRIS COCHRA PUBLISHED IN THE CHESAPEAKE SAILING YACHT SYMPOSIUM PROCEEDINGS For the 2014-15 Volvo Ocean Race, the organizing authority made a dramatic shift in direction for the next two editions of the race, opting to move to a smaller, less expensive yacht built to exceptionally strict one-design standards. is paper out- lines some of the motivations for this shift and details some of the critical features of the new Volvo Ocean 65 design and how they compare to solutions on the previous What are USCG/IMO Horn Requirements? Kahlenberg Industries, Inc. Two Rivers, WI USA Ph: 920-793-4507www.kahlenberg.com USCG/IMO compliant, ABS Type Approved sound signals USCG and IMO Regulations require a minimum output for horns on all vessels over 40 feet long. Surprisingly, many boats are fitted with horns and loudhailers that do not meet these requirements.Kahlenberg Horns are available in air and all electric versions for all types of vessels 12 to over 200 meters L.O.A.. Each shipment includes ABS Certicates to USCG and IMO Rules. Have a virtual blast...see and hear them at www.kahlenberg.com.