>>9691628Pink insulation foam. You can get it at home depot or lowes.
For 1/700 ships you can get a 4x8' for a couple of bucks, and just cut it out with a box cutter. You can then mold it form it however you want, a lighter can work to deform it for gentler sweeping waves, and just a dremel tool and some abrasive bits for more smaller scale waveforms.
For larger 1/350 ships they sell 1" thick pieces of pink foam that are thicker and more suitable for that scale.
Pic related, I've made a few sea-bases using pink foam.
