Upscale
How thick do y'all recommend making the water
Resin is only really helpful if there "things" to see under the layer.
Capitol ship anchorages tend to be about 100' or more deep--around 1.71" deep at 1/700.
Which would be deep enough to be able to tell there was no hull under the waterline ship.
So, at least for my 2¢, treat the base, as our wise GMorrison suggests as an opaques surface in a suitable "seawater" color paint. Then, finish with a clear get coat-like Gel Medium.
A light hand is wanted, though--waves 0.1" tall (a bit more than 2.5mm) are 6' to scale--which is a pretty serious "blow" in an anchorage.
I've used just gloss over "sea color" to give that "transparent at the top" effect; I've also mixed the colors in, too. Both seem to "work" at 1/700.
There's another strategy out there, which is to use aluminum foil to create the rillpled sea, then paint the "sea color" atop that. I've seen that produce spectacular results--and the price is hard to beat.