I am about to commit to a new fuel tank since my 40 gal fiberglass tank is disolving by ethanol. My dilema is if I should go with aluminum of Plastic. It will be a permanent V bottom tank for my 1989 19' Monterrey bowrider. I heard that plastic also gets the impact of ethanol and aluminum gets pitted over time. No way to win on this one?
Post this link in your browser for the best treatise on aluminum tanks I've yet to read. www.uscgboating.org/assets/pdf/recalls/BSC79.pdf
After reading that, consider that the installation is as important as the product. For instance, while aluminum will eventually corrode, making sure the hatch seals and O-rings above the tank are in good shape goes a long ways to forestall this. With a plastic tank, you have to account for expansion and contraction, which makes fitting it and securing it a matter of experience.
These are just two elements as examples.
The short answer though, is either is preferable to a fiberglass tank, especially given that ethanol levels in fuel are likely to increase.
I realize you are not dealing with a Mako, nonetheless, fuel tank replacement is a big deal for those of us with old Makos. Mine is a 1975, used in salt water and I had to replace the tank last year. Not bad for 35 years.
Anyway, go to classicmako.com and find more information about tank replacement than you want.
Also, thehulltruth.com has lots of info, just search tank replacement, but mostly they will refer you to classicmako.com. Classicmako is a bit slow loading, so be patient.