Boating How-To’s - Opinion-fuel tanks

Is there a reason that boat tanks are long and shallow? I will have enough room in my rebuild to have a mostly square tank. Anything wrong with that? Center of gavity or weight distrbution.... I would like to get your opinions. What about outside the stringers...
Thanks

Fuel tanks generally set between the stringers unless one has saddle type tanks (being outside the stringers). When we get the saddle type tanks to clean, we usually find one to be more contaminated than the other. Mainly due to condensation that has developed on the warmer/sunny side of the boat.

The shape of the tank doesn't matter much, within reason. No problem with a cube. The important factors are location and weight distribution. You need to be sure how the weight will affect the boat handling, and how the weight of the full tank will be distributed to the boat's structural members and how the forces from the mass of the tank will be transferred, in all three axes--down & up, right & left, fore & aft. Also, consider the use of baffles and how weight can shift with the boat's motion.

Changing the shape and/or location of a fuel tank in a boat can affect how the boat handles. Be sure you know what you are doing. Of course, the smaller the tank compared to the boat, the less the potential adverse impact.

I may be installing a bracket and twins so I could most likely use some weight forward. How do I go about finding balance points?

I may be installing a bracket and twins so I could most likely use some weight forward. How do I go about finding balance points?

the only sure way is to hire a naval architect. Short of that, you should talk to a marine fabrication shop that has done similar conversions.

What about plastic tanks? Are they as good as aluminum?