So after I finish my shack, I want to build a boat. Not something like an aluminum boat with a little put put 2 stroke motor, I mean a pumpkin-seed boat. (See: http://jimsboatworks.com/images/pumpkinseed2L.jpg)

Something like that but much thinner and much shorter. I was going to put a jetski engine on it, not sure of the power yet but I was thinking 150 or so. I am aware that that would be major overkill, but that's kinda what I'm going for with this boat.

My main concern is the stability of this thing once it has all that power. If I take a turn at high speed in this, I have a feeling that it will flip at 60ish MPH ripping my head and arms off in the process.

What can I do to make it stable? My boat is pretty flat bottomed, but it's slightly rounded, and I don't understand how it dosen't tip over as soon as you take a turn.

What I figured I would do is have the engines change pitch more and more the farther their turned. What I mean by that is that as it is turned farther and farther, the engine also tilts slightly up, forcing the ass it into the water and making the boat tilt against the turn like a normal boat so that it won't flip me over.

My other thing is that I want is that it needs to be very light and very tough because it will be traveling at great speeds. I also need ideas for the engine compartment

Any ideas/thoughts?

EDIT: So I've put more thought into this and I've come up with a plan. I might take a rather thin canoe (See: Old Town Discovery 146k) and chop it a little bit past the half way point, so it looks something like this:

http://i134.photobucket.com/albums/q104/midnightrider384/pumpkinseedboat.jpg

It basically follows the standard jet boat setup, just... scaled down a bit.

Put in a keel to make the boat more steady. Thats the thing that goes straight down in teh center of the bottom of the boat. Sailboats have 'em

i built a boat out of cardboard coated in packing tape for a design class last year.

http://www.postimage.org/Pq4BSaS-9d980d6e22b00fd4a384571d577dfe25.jpg

http://www.postimage.org/aVajrTS-9d980d6e22b00fd4a384571d577dfe25.jpg

the bottom was flat in the back and pointed in the front. it kinda tapered into a point. anyways, mine ended up buckling and folding in on itself in the middle. the front and back went up. before that happened, it was able to float, but anytime i moved, it rolled like a log in water. the bottom really needs to be flat.

http://www.postimage.org/gxbzUIJ-9d980d6e22b00fd4a384571d577dfe25.jpg

the 2 to the left are my teachers. the one on the left won the year before, and ended up surviving and taking 3rd the year i was in it. the one to the right of it, labeled #17, was the one he made for the year i was in it. it barrel rolled just like mine did. as you can see, a flat bottom really makes a difference.

in your design, you're all the way to the back of the boat. you need to be more in the middle, or at the very least, have something that levels it off. if the motor is in the front, it might weigh it down, but thats not taking into account it being on. you don't know how it will respond.

i recommend making a small model of it to put in a sink/bathtub to see how it floats before you go ahead with it. when i made my small models, i used manila envelopes coated in packing tape. you can push down with your hand where you sit, and weigh it down with random objects.

also, look at animals. they are made through evolution to be able to move through water fast. more animals have a rounded front/nose rather than a pointed one. thats because a rounded tip moves water better than a wedge. water reacts differently than air in terms of resistance.

most motor boats have their motor in the back, and there's probably a reason for that. if you put a rudder in the front and the motor in the back, and could either turn the motor or rudder, i think you'd have much more control over the movement of the boat than if the motor is in the front.

hope this helps!

EDIT: oh, i just saw you did have the propeller in the back and that was the engine in the front. maybe it'll weigh it down, i dunno.

most motor boats have their motor in the back, and there's probably a reason for that. if you put a rudder in the front and the motor in the back, and could either turn the motor or rudder, i think you'd have much more control over the movement of the boat than if the motor is in the front.

I'm not really worried about how much control I have over the boat, trust me if you've ever been in a jet boat you would know what I mean :D

I'm not exaggerating when I say that they can turn on themselves , it's that good.

I'm really only worried about tipping it at high speed.

With that hull design, I'd be worrying about tipping at a LOW speed.

Here's a good link to start at:

http://personal.eunet.fi/pp/gsahv/index.htm

Although most of those are not designed for motors.

Dug out canoe.

Aluminum is expensive. Use wood or some type of plastic or resin mold.

Modern outboard motors provide plenty of power, and using an outboard you dont have to worry about sealing the propshaft's hole. You can also get jet attatchments for outboards that will let you go like crazy. Check this out. (http://www.scottandjenn.com/outboardjet/jet_off_motor_big.jpg)

I'd use a slightly wider hull design for something like that as well.

Aluminum is expensive. Use wood or some type of plastic or resin mold.What about fiberglass?

Have you already used fiberglass? A boat hull would be a very big first project if you haven't. Wood seems to be the material of choice for DIY boatbuilders.

You could add some small outriggers for stability.

-N-

What about fiberglass?

that too.

Have you already used fiberglass? A boat hull would be a very big first project if you haven't.I'd have to agree. The first time I used fiberglass it hardly turned out like I thought it would. It's definitely best to start small til you learn the nature of fiberglass & resin.