This games looks promising, and I expect it to ba at least historically "acceptable". I'm far from a naval specialist but I agree that the ship models have wrong-looking sails... Is it that difficult to correct them ?
As for the graphics quality, the 3D looks Ok, but the bitmap images of captains (?) are so-so.. And indeed they look like 256-color pics - are higher settings supported ?
Edit : the ships'reflections in the water looked sometimes a little weird ... I checked some images, and indeed they are NOT reflections, but pictures some other ship !
Look at this, it's obvious :
http://www.spruegames.com/images/salvo/big/xebec.jpg
Surely it's a detail, but a rather too much seeable one ...