I would use a specialist Marine FEA package like Orcaflex to get fully coupled non-linear response.
Steven Rossiter MEng - University of Sheffield (Aerospace) - www.bpp-tech.com
Maybe the dropped object study is the best way to go. DNV generally recommends FEA be performed.
Steven Rossiter MEng - University of Sheffield (Aerospace) - www.bpp-tech.comhttps://exchange.dnv.com/Publishing/Codes/download.asp?url=2009-04/oss-302.pdf