The sea base has already been primed in "shade" of Vallejo Game Colour Imperial Blue (72020). To this a wet-brushed "base" of Vallejo Game Colour Magic Blue (72021) for a bit of variation. However the blue colour though nice is IMHO coming through a tad (Yorkshire for a little) too strong (see below):
Next step .. dull down those waves with a Vallejo Green Wash and help retire the "blue" to teh background (see below):
Next step take two .. add a partial (as in I do not have to cover every mm of the base) Vallejo Blue Wash over the sea areas (see below):
The "final" sea touch is to add back the wave tops with a delicate barely wet-brush highlight of Vallejo Game Colour Electric Blue (72023) which serves to suggest something 'wavy' going on (see below):
Next: Add some white-water oar and bow splashes.