Time to Flood Analysis For the Fishing Vessel ARCTIC ROSE Bruce Johnson, Fellow, U. S. Naval Academy and LT George Borlase, Student Member, U.S. Coast Guard Marine Safety Center ABSTRACT This paper outlines the hydrodynamic forensic analysis performed for the U.S. Coast Guard Marine Safety Center’s analysis of the sinking of the F/V ARCTIC ROSE. An intact and dynamic stability analysis of the ARCTIC ROSE in the reported wave conditions in that area of the Bering Sea on April 2, 2001 demonstrate that the vessel most likely sank due to flooding through an open WT Door. A time-domain analysis of various possible progressive flooding scenarios was developed in spreadsheet format to determine how quickly the ARCTIC ROSE could capsize using the assumptions for various ship motions scenarios. Using an iterative time-stepping approach to calculate the static equilibrium righting arms for increasing flooding loads, the righting arms for each time step were calculated based on the vessel’s position on the wave, flooding water height and location, and the free surface effect of the flooding water. The amount of water flooding from one space to another was calculated based on the difference in water height between spaces at open doors or hatches. The results show the ARCTIC ROSE most likely capsized between 1 minute 30 seconds and 2 minutes 40 seconds after progressive flooding began, due largely to the free surface effect of the water trapped inside the vessel. The fully pocketed free surface analysis methodology developed for this investigation is applicable for rectangular spaces in all vessels and has already been used to write an improved stability letter for a fishing vessel. NOMENCLATURE (Mathematical Symbols are defined in the Appendix where they are used.) FMBI Formal Marine Board of Investigation FS Free Surface Effect F/V Fishing Vessel GHS General Hydrostatics Program GM Metacentric Height IMO International Maritime Organization KG Distance from keel to center of gravity LT Long Ton MAIB Marine Accident Investigation Board (UK) MSC Marine Safety Center (USCG) NMFS National Maritime Fisheries Service RA Righting Arm SSPA Swedish Hydrodynamics Laboratory USCG U. S. Coast Guard WT Watertight Figure 1 Bow view of the ARCTIC ROSE 1. INTRODUCTION AND BACKGROUND At approximately 3:30 a.m. on April 2, 2001, the 92 foot (waterline length) F/V ARCTIC ROSE (Figure 1) disappeared in the Bering Sea, approximately 200 miles west of St. Paul Island, killing all fifteen men onboard. No Mayday calls were heard, nor were any distress signals sighted. The U. S. Coast Guard convened a Formal Marine Board of Investigation (FMBI) to determine what happened to the ARCTIC ROSE, why it happened, and how casualties like this could be prevented in the future. At the time of the loss of the F/V ARCTIC ROSE, a low pressure system was moving through the area, and