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Hull Design ?

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Airhead

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Trying to decide whether or not to put a slight degree of "V" in the bottom of an aluminum airboat hull or not. I've got the option to go with a completely flat pad or put about 1/4 to 1/2" of bend or bow creating I guess a slight pivot point in the middle of the boat. I would think the only thing it would help is to eliminate suction but will it hurt my ability to plane out quickly or hurt my top end speed?

I'm used to running wide flat bottom jon boats with an outboard jet and for us the wider and flatter the better for quick planing and carrying a load but we are really never shallow enough to have to worry about suction etc. When you do it's too late.

It's a small lightweight airboat and I do not need nor expect it to run dry and my major concern is getting up as quickly as possible and running the fastest with a load.
 
From what I know (????) when you get your boat up on plane it is only riding on the the rear of the hull. When mine is close to wide open, it pretty much is only riding on a couple of inches of the hull. I have never heard of anyone doing what you suggest, but I think you will be making a big mistake. I will give you a example, I added 1/8 " of fiberglass mat on the rear bottom edge of of my hull. It covered 1 1/2 from side to side. The purpose was to correct the bow from bouncing, I had to grind some off!! Very small changes in the hull make a big difference. Also a perfectly flat bottom is what you want, same as a boogie board or surf board. Just my opinion, but I'm not as smart as I used to be.
Rick
 
I have seen the v in the bottom of a fiber glass hull chuck at air boat pros showed me in that pro stroker 148 boat that there is a slight v in the bottom also said that it helped on dry gorund because you could rock it not as much surface on the ground .he also said that it rode great.
 
I think slightly rounded side-to-side and front-to-back produce good handling both wet and dry.

I believe a v-bottom would make it harder to spin around on dry ground.

I wouldn't do it, but you could try it and let us know :D
 
The slight degree of "V" would be constant from the rear of the boat to where the front starts to rise. So I'm not sure it's like adding a strip of fiberglass across the rear of the hull at all. I can do either 1/4" or 1/2" and I'm thinking if I do it at all I would go with the 1/4." I think the bottom of the hull might even be stronger with a slight bow in it and I want to try and avoid ever having the hull sunk in or depressed across the bottom which as I see it would create a major suction cup and problems all the way around.

I forgot to mention earlier that it's a 60" pad at the transom and if you had a 1/4" bow in the middle approximately what degree of "V" might that be. I know that alot of the jon boat manufactures have what they call semi v hulls that have a 6-8 degree of "V" all the way to the back of the boat which does not seem to hurt their performance but it's for running more choppy water which will not really be a problem for me. Again my concern is if I'm sitting in 3 or 4 inches of water and the pad is on bottom would it help me break loose without sacraficing performance otherwise. I realize this is a different application but how does it translate to the airboat hull.

So the question remains to "V" or not to "V"?

Thanks.
 
I say "V" because I'm not familiar with the terminology but in effect it will be rounded from side to side. Imagine a piece of aluminum 60" wide with a low point in the center of 1/4 to 1/2 inch below the sides created with a bow. It would not be two straight lines to a point in the middle.

That being said do you think 1/4 or 1/2 inch.
 
it will have a slow rock from side to side as you run on a plane thats what happened to my 14' diamondback when I put 1/2" in both jacks so I took it out of the rear
 
I tried a slight V shape in one of my airboats. All I’m going to say is I hope your running a 200HP or less motor because if your not your going to be very unhappy.
 
Waterthunder it's not really a V but more of a bow from the edges of the pad in to the center or slightly rounded as RD said. That being the case and it's less than a 200hp motor would you have him add the bow or just keep it perfectly flat across the pad?
 
I had a hull built with a slight V, it was really more of a slight round in the front area. All that hull did was ride on the nose. Just give her gas and the bow went under it was the worst hull I ever owned. I know three other people who tried the same thing and they all had the same results I did.
 
The hull would be slightly rounded width wise at the rear and continue forward to the rake. I think it would have a long ways convex shape and would pivot slightly from side to side if on flat ground. Does that change any thing or would you recommend a completely flat pad?
 
The pad (what would normally be perfectly flat on the ground) is going to be 60" wide at the transom. Then it starts to round up on each side.

The entire 60" piece will bow as I understand it. The best way I can explain it is take a 60" piece of aluminum and press in on both sides causing it to flex downward or bow our however you want to look at it. So I guess to answer your question none of it would be perfectly flat since it will have a slight bow from side to side.
 
Seems that some of the larger airboat companies have the same bow I'm talking about on the bottom of their hulls. One I talked to said 2 or 2 1/2 inches across the back of the boat and the other said approx 5 degrees of rise from the center out. I believe that is what they call dead rise. When we put pontoons or planing boxes on our jon boats they have a slight degree of deadrise from the rear of the boat out with the transom kind of being the pivot point.

Is the purpose of the bow to put less boat on the water or ground for reduced friction? I guess it creates a teeter totter effect rocking from side to side when trying to break ground and I can imagine that when running perhaps you have a little less boat on the water. I can really see the advantage when sitting on mud or dry ground but when getting up it would seem to part the water instead of letting you climb up top. Maybe it's not enough bow to make any difference.

I'm leaning towards a 1" bow across a 60" pad.

What do yall think?
 
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