It was an attempt to create a nice ripple effect - it kinda worked, but created bubbles which had to be smoothed out.
If I try that again, I might try wetting the surface first.
Super little resin kit by HP Models (Germany). You need a scalpel just to pick up the tiny bits. Took me 3 hours to assemble the ship - I won't dwell on that, but here's how I did the sea and paint etc.