Local, coastal sailors never see warm water around here, unless they lose sight of land (OH! HORROR!) in August when the Gulf Stream changes, then it gets up to 20 C!
For the small, medium speed engine you describe, (sounds like a B&W Alpha) find out the ambient air dew point (the wave watchers can help you out there) and keep the turbo aftercooler outlet temperature just above that. Maximise the air density, but keep the water as a vapour so it goes through the engine, don't condense it out. Liquid water in a cylinder does funny things.
Discourage incest, ban country "music".