>>96785907
Dunno about best but these days you got choices. Ainsty has resin ones and Firelock Games have them as essential parts of their Blood and Plunder games.
You can also get mdf kits which can be cheaper, but don't really necessarily look as good. There are also some old scale model kits I've seen people use, but if you want something actual in scale with the minis those get huge and expensive quick. The smaller models are not really very playable.

If you dig around in an old White Dwarf archive you'll also find a couple of article about how to scratchbuild ships for various Middle Earth scenarios. Basically just making the body with foam and cladding the sides with cardboard iirc.