Posted by JimM on October 10, 2002 at 06:33:36:
In Reply to: airboat cobble posted by Aaron on October 09, 2002 at 11:31:00:
Last week we had a big discussion on the forum about stability - a guy was trying to sell a little hunting boat which was inherently unstable and, in our opinion, dangerous!
A 16' jon boat is stable enough for rowing, or maybe powering with a 3 horse kicker. But I would not attempt any kind of speed in one! If (I should say, "when") a chine digs in, it's gonna go over, right now! With the speed, you'd be very likely to be injured.
I also worry about the weight of two VW engines and the structure and cage for the prop. A 16' jon boat simply isn't designed for that much weight. I don't think you'd have much freeboard left over!
You've probably seen "real" airboats. Think about their size and carrying capacity. They aren't any bigger in capacity than what you're thinking about, and yet they're a lot longer and wider (and more stable). And the prop tends to be rather large, too.
When I was a kid, I wanted to do the same thing you're suggesting. I was less ambitious - I was going to use a lawn mower engine. The jon boat was only about 10', and I had a prop which I think was from a drone or something. If I had ever succeeded in putting anything together, I doubt if my Dad would have let me start it up!
I hate to bring discouraging advice, but... you asked! Don't want to see you get hurt, either. How about a much smaller engine, just to get a feel for how an airboat behaves? Please make sure you install a cage - it's probably a Coast Guard requirement.