I havn't had a ship suicide in my tree, but I have had a murder, accidental drowning on board ship,& a possible suicide (unproved), for all of which I gained information from the Local & National Newspapers. I guess you may already have tried them. Suicide not being that common it may have been quoted in 'The Times' along with their other info re shipping, his local paper, or those of the ships Port of Registry. It might be worth an e-mail. Good luck.