Poor man’s cat

[beerbelly]

ok cheers i have someone wanting to buy the longshaft so i might look into a permatrim or fins or experiment with the 5hp or the 8hp

[beerbelly]

any more updates or is work getting in the way .mine turned up in the post but as i am getting ready for a week with the humber up at easdale next week its not even been looked at yet

[harrison]

Sorry matey, no updates for a week or three.

Reckon we need more power, bigger AV plate and a non plastic prop for any serious testing....might even need a dreaded hydrofoil.

No mileage in butchering more off transom methinks as this will potentially cause more issues at non planing speeds. On the hunt for more power, and making interchangeable pads for an adjustable height transom.

Bottom line, don’t reduce transom if happy at non planing speeds with low power motors. Works ok out the box with up to 3.5hp standard shaft at displacement speeds, and even better with a long shaft which will just get it planing. For more serious fun it’s gonna need further work.

Being so tiny a hoot at planing speeds one up. Playing in the (small) surf zone so far experienced some serious bow steering moments and a couple of full ‘stuffings’....the air floor just floats when the hull fills...cool or what!

Not for the faint hearted, but bleedin good fun.

[Fishingribs]

Hi Harrison, greetings from Switzerland . Thank you for sharing your experience with Air Cat. Can you share if the. Oat came with the Declaration of Conformity? Did you get the import declaration as well? Here in a Switzerland both are requisite to get the registration. Thanks in advance for your time. Cheers!

[harrison]

Hi @Fishingribs, welcome to the forum.

The boat came with only a user manual, and unfortunately this did not include either a Declaration of Conformity or Import Declaration I’m afraid.

I would assume these could be requested from the manufacturer/importer if required.

[harrison]

Quick update.

Unfortunately no further on water testing with the little 3.5 Mariner’s since butchering transom due to recently furbarred back, free time and sea conditions out of sync etc. etc. but have been busy in the shed.

Don’t think there’s anything to be gained going lower even though motor still ventilating, and the little 3.5’s plastic prop, AV plate and lower leg profile may just not like running at planing speeds. Have recently acquired a cheapo Chinese lightweight 8hp four stroke motor which should have enough power to easily get the little cat planing.

We also now have the flexibility for quick change transom heights as cobbled together a set of bolt on interchangeable transom pads able to go up or down in 15mm increments.

Conscious of the fact many motors just won’t perform on cat hulls without the addition of doel fins and/or cupped props, both of which reluctant to do, so a bit more cobbling. Basically a sort of central trim tab to hopefully smooth out the water flow before and over the prop. Exact angle, height, whether it has any effect or not....not the foggiest at the moment, but simple and quick to bolt on/off for testing.

Phase two testing to commence as soon as back, weather gods, and free time are in alignment.

[Oldman]

Nice workmanship there, but wont the wife and next door miss all those chopping boards
You must have a secret low cost supplier.

[Froglet]

I like the look of the Orca 8hp. Assuming they did a faithful copy of the Yamaha 4/5/6 it should be nice little runner. As long as boring it out hasn't left it fragile or anything.

Funnily enough I finally acquired a Yamaha 6hp and that's capable of pushing my T38 up to about 12.5mph (so far; more testing required). That's solo, but with a fair amount of luggage and fuel, so I'm sure your cat will be flying with the extra couple of ponies.

The trim tab is worth a shot. Hope it helps smooth the troubled waters.

[sonny1]

ian @harrison you are one very clever man ,,, but im sure you are too modest to admit it . good on yer . B.T.W. i know its late but you can jump in with me tomorrow if you fancy a significant run out , should be really good

[harrison]

@Oldman Yeah, IKEA. Used to be a quid each but shocked to find they’re now £1.75....glad we have a stash!

@Froglet the Yamaha 6 is a great little motor...any pics?

@sonny1 Oooh thanks for the invite. Unfortunately still up north at the mo so will have to pass, shame. Weather looking good so should be a great trip, might even make Lulworth with a bit of luck.

You be sure to keep a weather eye open in them there pesky overfalls mind.
Have a great run.