If you download IABL's
Merchant Fleet Mod for SH3 you will get more than 70 new models plus special listings for different navies. Many of Lurker's OM ships are taken from IABL's models. You will also find a set of skin packs that add even more to the variety.
Couple that with SH3 Commander and my Ship Names mod and you will not only get hundreds of different ships to sink but each one will add a name, cargo loadout, crew number and crew lost number to your Commander log, which can then be placed back into your SH3 patrol log.