I have been looking for a gas tank for the boat. I think even my 311 may need one as well. The old tanks in the boat are alluminum. I have been researching this quite a bit and it looks like the ethenol is going after welds on allum. tanks. Stainless you can only use with Deisle. Also Alum. tanks are not to be foamed in (even though every boat manuf. that I have ever run into does it). So I started to look at polymer tanks. They do make them large now. Does anyone see any down side to this?