Del, I don't know what to suggests, but it sounds tricky!! If you shoot RAW you can do the warming in the post processing, so it sounds like a good idea to use a CP filter to at least get rid of water reflections if it's bright sun, and also give you some rich and yummy skies!
But just shoot as if the bride would be a ton in size, i.e. with a huge white wedding dress (the sails) and expose according to that. Check your histogram, it will proably peak near the right, but not let it trail off too much on the right, so that the images are over exposed. (It's like shooting in snow, you will risk underexposure since the camera will be fooled to think it needs to make things darker). If you use the flash for fill, it'll help you a bit, and if no flash, use the EV to increase it a step or maybe two (depending on how it looks). The highlight warning could be a good idea to use until you get your bearings.
If it's sunny, you might get harsh shadows, but you also have the sails as a big white reflector, so try to use that to your advantage, i.e. shoot them so that you can "kill" some of the harsh shadows using the sails as the reflector on the shadowy side.
Oh and just for me... if it's possible... I'd like to see a shilouette (spelling?) with them kissing through a sunlit sail... it would be soo cool... well if it looks like anything in my head. The sails might just bee too big.