Waterproofing really depends on exactly what materials were used to build the hull - Balsa needs much more work than ply or solid timber, plywood can either be marine ply which is designed for a certain amount of exposure without delaminating, or cheaper ply which will quickly fall apart in a damp environment.
The rails can be made from wood, or metal rails with a wooden top rail, or all metal..... It all depends on the vessel being modelled.
If you give more information on the materials you've used for the hull etc a full explanation on sealing/waterproofing can be given.