Hidden under the seats are 12 gallon FRP fuel and water tanks, each built from a resin rated for the material contained. They hang from the seats via a flange extending from the lid of the tank. They weigh only a few pounds empty, clear up the deck and hulls, and add range.
We added strength inside the front of the hull under the round hatch above. We also added a floor board which makes it sooooo much easier to climb down through the hatch.