Hello Paul,
Models by design use to make a fibre glass hull about 8foot long not sure if they still make them, if not a VLCC, ULCC hull is really just a long box with a bow and a stern put on the ends drill holes in the bottom of the long box so its free flooding only thing you have to make is the top sides I as a young man worked BP Tanker Company on VLCC,s most was 250,000 tonners my smallest was a tiddler 115,000 tons was only sea sick once on a Liberty boat ashore in Tokyo bay to Chiba I would like to make the tiddler BRITISH ARGOSY built on the Tyne.
Regards Howard.