Cat Hull

[theboysmiffy]

Hi everyone. After years of windsurfing I've deceided to join the motor powered humans! Just bought an old ex Navy 3.6m SIB with ply floor and inflatable keel. The tubes look to be oversize. Shes not pretty but functions well. I have also purchased an Evinrude 2 stroke 35hp outboard to go with this. I know thats a lot of power and weight for this craft. I was wondering if anyone knows if it is possible to modify the tubes on this craft buy adding smaller ones and creating the catermeran hull? Are these available off the shelf and how do they attach? Any help and comments are more than welcomed.

[chewy]

Whats the reason behind adding the extra tubes?
I know Zodiac call them speed tubes on the Futura.
You could get some made but I don't think it would be worth while. It should be great fun as it is!

Welcome to the forum.

[theboysmiffy]

Thanks Chewy. I was thinking that they enable the boat to plane more easily, sharpen up the handling and increase to speed. I think I will enjoy it as it is for the time being but it might be a project for the future. Ive always quite like modifying things!

[Polwart]

Originally Posted by theboysmiffy

3.6m SIB with ply floor and inflatable keel....... Evinrude 2 stroke 35hp outboard...........I know thats a lot of power and weight for this craft..........enable the boat to plane more easily, sharpen up the handling and increase to speed

[theboysmiffy]

I'm guessing that means you don't think it will work with the tubes or even without them??

[SeaSkills]

Originally Posted by theboysmiffy

I'm guessing that means you don't think it will work with the tubes or even without them??

I think that maybe they're saying you should proceed with extreme caution. That does look like a lot of power (and weight) for that boat

[theboysmiffy]

Thanks for the advice, obviously I appreciate that you all have more experience than i do with these type of craft. My intentions are to familiarise myself with the setup slowly using little throttle and smooth openings and closings. Any advice is greatly appreciated and taken on board.

[m chappelow]

think you will find that its probely at its max speed and power levels as it is for a boat that length ,by adding tubes under the hull might also lift the engine up to far out of the water once on the plane causing airation cavitation i would leave it as it is ,any idea on the make of your boat at all .

[theboysmiffy]

Really not sure, can't find any info anywhere on it. It looks a bit tatty but doesnt leak air or water and all the joints seem good. These were taken before we took possesion, minus the ply floor and in need of a good clean! Any ideas?

[chewy]

Sell it to me!

I'd take care with the outboard, it should fly with a 20hp.