On my 1/350th subs and ships, I create a base out of red oak and use small blocks to sit the model on, kind of resembling keel blocks(way over size but very stable). I select and cut a board about the same length and width of the model, bevel the edge, and sand, stain and finish it. Cutting 3/4 by 3/4 inch lengths of oak to make the crossways pieces, having the bown and stern pieces narrow and widening out for the amidships of the ship or sub. Inside the model, I glue some thick plastic down in on the bottom of the hull in several places, this gives you something substantial to screw into. I measure the length of the hull on the big board and make reference marks where the added plastic is at. I space out the 3/4 blocks to give a pleasing look, about 3/4 of an inch or so apart, looking to have a cross piece under the added plastic in the hull, where a long screw will come up through the bottom of the base board, the cross piece and into the hull bottom. A little torque with a screwdriver snugs up the hull and base, the screw should not be visible(note:predrill the screw hole through the base). Finishing the bottom of the hull of the model is, of course, the first thing to be done. Once the hull is attached to the base, you cover the base up with masking paper, and thereafter have a very secure and heavy base from which to continue working on your model.
