I build all genre of models, so have contact with each community. Model shipbuilders are the most likely to scratchbuild of all the genre (except for model railroaders who scratch a lot of their buildings and scenery).
Most ship scratchbuilders of ships build in wood, however, rather than styrene. A common technique for hulls is the "bread and butter" style, where one cuts several planks of half inch or so thickness to the planform of that hull at that elevation (these planforms are included in scale drawing sets of ships). Because there are so many scratch model shipbuilders, there are more scale drawing sets (plans) available for ships than any other genre. Now, these are scale views of the prototype, not step by step instructions.
There are places that sell a lot of "fittings" for scratch builders, plus there are lots of PE sets available.
The classic book on scratch shipmodeling is "The Built-up Ship Model" by C. G. Davis, but it is aimed primarily at sailing ships.
I suggest picking up a copy of "Ships in Scale" or some other ship modeling mag at the hobby shop, and also look at the Model Expo and Bluejacket web sites. They both carry books on ship modeling, plus the fittings and things.