• If you log in, the ads disappear in the forum and gallery. If you need help logging in or getting registered, send request to: webmaster@southernairboat.com

Proper Balance of the Airboat

G

Gbenzx

Well-known member
Is there a formula that is used todo this or is it a copycat type of thing?

Have heard of old timers talk abt using ballast in a floated hull to arrive at placement of engine in I/O boats.

Not too many home made boats anymore but how can they possibly know where to mount the engine?

I've been advised that when I find a hull of whatever size it may be to take it to a boat builder that knows where to put the engine & other ingredients that make an Airboat.

Is there something someone isn't telling abt this?

Thanx, Gben
 
I don't think it's as big an issue as it seems. When we built my rigging for my boat we knew it was going to be direct drive and I was going to use a 72" long prop. I built the stand in the boat without it attached to the stringers so that it was high enough for the prop then set the engine on with the prop on it and slid it back and forth until I got the measurement I was looking for to clear the transom. With my chevy engine on it I ran the prop 4" from the tramsom for clearence. I also built it so the prop tip was at the level of the tab on the transom to keep the wash out. It ran pretty good that way. Wen I changed over to the Cadillac engine I slid the engine forward so it is about 12" from the transom to the rear engine mount. It didn't effect my boat at all (as far as how it rides) but it don't sit any lower in the back than it did with the 350 chevy. I'm sure you will get a lot of different opinions on this. I just wanted to show that I had it set up 2 different ways and the boat ran the same in the water.
 
On the boats that I have built and helped build, I have set the prop about 4 inches from the transom with both d/d car motors aircraft and with gear boxes all worked out the same, thats with the prop on and the motor and the motor on the stand. then I build the rest of the metal work to the stand to match the hull size. If you are using a long hull [over 12-13ft] you could go a few more inches if you want to help keep it from hopping in the water.
 
Thanx Guys

Some of the very stuff I was looking for :)

Dan, what is the length & width of your boat?

Also do ya'll have a set pitch(up/down angle) for the engine/prop togo by? Or just align with the boat?

Gben
 
my boat is a 15 x 7 1978 Panther aluminum hull. And I asked the same question about engine angle from a few guys in my area and the told me that the engine should be level with the stringers. And ride adjustments should be made with bottom jacks or a trim tab. They said that engine angle makes too much of an impact if you chage it and the jacks will "fine tune" the running surface.
 
Thnx Guys

Const tore phonelines down & this little cell hooked to this thing in NC is have a prob seeing over the mtn :(

More later Gben
 
Hope all you Guys down south are coming out ok after Katrina.

Our Earthquake only gave us a small flutter & widened the crack in our chiminey a small bit from the one we had last time. Phone lines are still messed up but got the cell hooked up to our big antennae :)

If going from a small engine to the big cad engine was not a prob in a 7 wide hull then I feel it will be ok in our comfort zone also. :)

Some good pointers on the site here abt jacks & sense no response from the folks down here must not be much of an issue.

Thanx, Gben
 
You must log in or register to reply here.
Back
Top