Jake,
I've never tried this for sailing but it might be the solution to your "foggy" problem. Theres a product out there called Fog City that is made for motorcyclists. It is a film that goes on the inside of a full-faced helmet and keeps it from fogging up when the faceshield is closed. It would probably be worth trying a sheet and cutting it to fit your glasses/goggles. I think it runs between $15-30 a sheet. Here's one link:
http://www.modernworld.com I can attest that the product does work very well for motorcycle helmets.
If you do try it out let us know how it works.

EDIT: Even better would be to call them at 800.436.4248 as ask if they know the effects salt water has on their product.