Originally Posted by theboysmiffy
That looks like a similar concept to what I had in mind. Triangulating the floor and transom has got to add strength, eapecially with some stainless steel.
It is a nice idea, hoever, you'l loose on the space near transom, gas tank and other thinks will be less easy to organize. There is an easier alternative, that you could use as an option.
You could have a look at your local harware store for a plastic tool box/cooler kind of thing.
In the box you could store your gas tank and other small items. Drill the hole for the fuel line and wires. You could sit directly on the box with motor behind you, easier to steer and better balance for the boat and as well as safer, then sitting on the tube.
Here is the reinforcement part, that I've seen somewhere, but can't remember now where....it is way simple as well as adjustable, and I'm not surprised if is more rigid as well.
Place the cooler at the transom, attach rachet belts with bolts or fat screws to the transom and the coller from each side, going from the top of the coller and reaching from the top of the transom to the back. Once you sit on it, your weight will act as counterweight for the motor. Since it is only reinforcement and assuming the transom itself can hold weight of the motor on its own then this should work rather well for you.
For even greater strength, you can attach the front side of the coller to the floor, this way the floor will also act as the counter force for the motor weight.
By installing the cooler/box you'll get: extra seat, storage compartment and reinforcement at the same time, means more comfort and safety for you and your friends.