Petrol powerd :-) kayak catemarn

[lorne.elleby]

Easy enough done with x2 kayak's a few strips of aluminum poles.

.....BUT instead of an outboard.........

is it possible some how (please dont laugh),

to run a 110cc semi auto midi moto engine (below).



im not sure on how to protect the engeine from
salt water and how to rig the engine to a prop.

any help would be appreciated!


Thanks Lorne Elleby! :-P

[lorne.elleby]

Motor detais.

110cc Loncin single overhead cam, single cylinder, four stroke, four-speed semi auto, electric start engine.

Comes with starter motor and wiring, kickstart, 14 tooth drive sprocket, sprocket cover, inlet manfold and gaskets.

There are two versions of this engine in production. This is the better cylinder head version with the roller bearing cam.

[mybrainhurts]

Take the handles off one these, hang it on the back, and you've got your own mini paddle steamer...

[lorne.elleby]

Thanks for that!

but i already got my mind set on a midi moto engine! hopeing to do atleaset 25mph if not more!

[dugt]

its definitly possible to do, make up some frame work to hold the engine, propshaft onto the sprocket ongearbox

the big question i would ask is will the kayaks be over powered making it undrivable, rememebring that a kayak is designed to be propelled by a bloke with a paddle,

but yeha, definitly possible

doug

[lorne.elleby]

thanks doug!

any chance of a simple drawing showing me, possibly use MS PAINT?

[lorne.elleby]

this is the lay out i was thinkin for the support beams.

[mybrainhurts]

Are you going for a round the world....?

[lorne.elleby]

this is the idea i have to mount the engine,

Not sure if its ok to get a chain going in to salt water?

[GreenV8S]

Why do you want to do it?

Do you know enough to do it safely? Chains and propellers flapping around can be very dangerous.

[lorne.elleby]

Re: mybrainhurts


nope just a small fishing craft me and a freind could go a mile or so out.
thought it would be fun to do.

im not sure if its all leagal, if any one knows please let me know!

[lorne.elleby]

RE: GreenV8s

My knowledge is thin! i was hoping to learn a bit from fellow PHers.

i know a outboard motor will be allot easier, but its the fun of attempting.....isnt it?

Im not going to be an idiot and take it strait for sea trails and have the RLNI towing me back ashore, we have a river and sailing lake near by witch trails could take place.

I defiantly think a couple of paddles, life jacket, and maby a marine radio could be helpful for an emergency!

But damn can no one see the fun in this if it works?

25-30mph on water then an afternoon of fishing, some one must agree!

[lorne.elleby]

i have another point to my favor.

3 words!

Scrap Heap Challange!

[GreenV8S]

lorne.elleby said:

25-30mph on water then an afternoon of fishing, some one must agree!

If you want to have something useful at the end you're probably barking up the wrong tree. If you're doing it for the engineering challenge, prove you can make it work and then throw it away then go for it. I'm sure you can find an old bike engine in the breakers yard that will have more than enough power. Just make sure you have plenty of guards between you and the engine, chain, prop etc. And don't take it out further than you're prepared to swim back.

[Pigeon]

Chain going into the water like that will fling water EVERYWHERE and make a heck of a mess. Will also be operating pretty much unlubricated... though this doesn't actually matter too much as it probably won't wear out the first time you use it, and there won't be a second time, not for that chain anyway after it's had salt water corroding it into a solid orange lump.

So you really need to enclose the whole chain in a solid waterproof box with the prop shaft emerging through a seal. Shaft seals are easy, making a big long completely-sealed chain case less so. You'll also be after needing some sort of brace on it to stop it flexing fore-and-aft.

A bike engine used at sea will also corrode like a bd, and you will never be able to service it because none of the bolts will come out. So the engine too needs to be totally enclosed, and you'll need a water-cooled one so you can mount the rad outside the box, or else use a water/water heat exchanger to dump the heat into the sea.

The prop will also be operating under somewhat less than ideal conditions due to the width of the drive sprocket and surrounding case immediately upstream of it.

You are basically going to end up building an outboard, only it will be heavier, more cumbersome, more expensive and worse performing than a boughten one. It's only worth it if it's easier to find individual sums of money one at a time to build the various components than it is to find one big lump to buy an outboard - which given the existence of some pretty cheap outboards on ebay is unlikely to be the case - or for Scrapheap Challenge where it only has to work once so you can omit most of the waterproofing.

[Pigeon]

...Have you thought about making a longtail instead?

[dugt]

lorne.elleby said:

thanks doug!

any chance of a simple drawing showing me, possibly use MS PAINT?

ill give it a go and try and make a pic now

doug

[dugt]

ok, ive done a quick drawing

here goes



ive put the engine more in the middle, as it will probably weigh a bit more than the small outboard, so might help stability

the frame, the more triangulation the better, will make it stronger

on the engine, there will probably be a sprocket like this


youd need to attach the propshaft to this, this may involve welding/drilling/swearing, but it will depend on whats on the engine

in my design ive put bearings in, i dont think it would need to be that precise, but youd need away of keeping the propshaft in line

then obviously youd need the proppellor at the back, obviously put some kind of cover over this to stop it mincing people


the thing i havent included in my picture are

• petrol system, your going to need somewehre for a fuel tank/pipes/pump
• electrics, the engine may have a kind of dynamo on the crankshaft so that might make it simpler
• some kind of steering device, my design doesnt ave any steering
• some kind of stopping, most boats ive driven, you stop by going into reverse, but i doubt a motorbike engine has a reverse

disclaimer
im not a boat designer, but my girlfriends dad builds/designs/oversees containor ships/ferries for a living, but ive never spoken to him about boats, not once

and if you kill yourself, its not my fault

have fun
dug

[lorne.elleby]

cheeres for that doug look alot better that my original concept i will take your ideas onboard and hopefully come out clean, the prop shaft seems to be a much more probable idea!

thanks for all the contributions from every one, should be one hell of a water craft, will keep you all posted on construction!

thanks lorne

[dugt]

if you dont get killed, horribly, remember to put some pics up

you probably want some kind of rudder at the back, either one behind the prop in the middle or two, one on each kayak
and remeber you wont be able to stop all that quickly

doug