Cat Hull

theboysmiffy · 30 July 2009, 08:32

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 · 30 July 2009, 08:39

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 · 30 July 2009, 08:46

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!

Poly · 30 July 2009, 10:25

Quote:

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 · 30 July 2009, 11:37

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

SeaSkills · 30 July 2009, 12:57

Quote:

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 · 30 July 2009, 13:05

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 · 30 July 2009, 13:49

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 · 30 July 2009, 14:18

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 · 30 July 2009, 14:34

Sell it to me!

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

theboysmiffy · 30 July 2009, 14:38

Looks very stealth doesn't it? Balaclavas are mandatory! We are going to tidy it up and have some fun with it. The boat and out board didn't cost that much in all, well compared to newer machinery.

m chappelow · 30 July 2009, 16:43

not too much up on m.o.d. boats but my first guess is it looks like it could be a gemini ,though parts it also looks a bit avon and zodiac lol.,,,,,you may find that if you use it in certain areas eg major ports /petro chemical and dock areas you may get the local plod inspecting you until they know who you are ,one good thing is it wont show up dirt lol ,, mart,

Poly · 30 July 2009, 22:35

Quote:

Originally Posted by theboysmiffy

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

I'm saying I think it will be "interesting" enough (or possibly shit scary) as it is without needing to add anything to increase the terror levels.

Sharkbyte · 30 July 2009, 22:53

Quote:

Originally Posted by m chappelow

not too much up on m.o.d. boats but my first guess is it looks like it could be a gemini ,though parts it also looks a bit avon and zodiac lol.,,,,,you may find that if you use it in certain areas eg major ports /petro chemical and dock areas you may get the local plod inspecting you until they know who you are ,one good thing is it wont show up dirt lol ,, mart,

Lol, they will think he is the waterborne plod.

Even on our bright red Futura, commercial fishermen scurry around hiding / throwing things overboard when we approach, nocturnal unlicensed netters sh1t themselves, other boats suddenly decelerate in no wake zones and yachties call us over and ask us stupid questions in plummy voices.

Poly · 31 July 2009, 07:51

Quote:

Originally Posted by Sharkbyte

yachties call us over and ask us stupid questions in plummy voices.

one tried to pay me mooring fees once... I thought it was a one off - but you have just highlighted a potential scheme to fund a boat upgrade!

theboysmiffy · 31 July 2009, 08:06

Cheers for the response. Quite like the idea of unintentionally intimidating!! I think your right Polwart, I'm just going to use it as it is for the time being until I get used to it. Then next year . . . Inflated it in the living room last night and it measurers 3.9m from bow to stern. assuming you take the measurements to the end of the pointy bit of the tubes (not sure what they're called?). There's definately no markings to identify it with. it has grab ropes running the length of both tubes on the inside and outside and six inflatable chambers including the keel with another four dummy valves which have no actual valve fittings in. Where black sib's readily available new, I would love to know the history of this craft?

theboysmiffy · 31 July 2009, 08:53

If any one could help identify this craft and more importantly what it is made from that would be great as I'm looking to make good some old repairs.

chewy · 31 July 2009, 09:04

I would have thought Hypalon if its ex-mod.

theboysmiffy · 31 July 2009, 09:06

Is there a way to tell the difference?

m chappelow · 31 July 2009, 09:44

[QUOTE=theboysmiffy;307561] . Quite like the idea of unintentionally intimidating!!,,,There's definately no markings to identify it with.

dont think its about intimidation They might think you are the enemy as the way things are at the moment ,lol and on the subject of no markings,,,,you wouldent want to land on an enemy beach hide it and some enemy soldier comes along and its got union jacks or avon made in wales labelled all over it lol ,,,as chewy said it will be hypolon material ....regards the dummy valves some boats are fitted with a single point valve for quick inflation ,eg submarine operations ,by a gas cylinder ,,,by the way is the engine painted green or is it a civilian model ,regards mart