Comparative Analysis of Stern Ramp Sea Trials Results from a 154 ft Patrol Boat and a 418 ft Cutter

摘要

Comparisons of the launch and recovery performance for a patrol boat and a large Coast Guard cutter, based on numerical seakeeping calculations, were presented by DeBord at the 2012 Launch & Recovery Symposium. Recently, sea trials were completed on the USCGC PAUL CLARK, providing measured data for the patrol boat. This new data set is presented and compared to launch and recovery data collected in on the USCGC BERTHOLF. The paper is focused on two primary technical areas: (1) relative performance of stern ramps on patrol boats versus frigate-size cutters, including discussions of the response characteristics of these vessels that cause any differences; and (2) evaluation of numerical seakeeping programs as design tools for assessing stern ramp launch and recovery performance. Key points to be discussed include: 1. Comparative stern motions for the two vessels and the effects on performance 2. Differences in stern ramp design and their effects on performance 3. Operational approaches to maximize performance and minimize risk 4. Comparison of seakeeping predictions to trials results 5. Discussion of limiting conditions and the factors affecting these limits for both vessels.