View Full Version : Hull Plans for an Airboat
03-04-2008, 10:37 PM
Never mind anything I said in the "Bending Aluminium" thread about building a boat. Part of the conversation that brought up my friend's idea was that I was talking about building an airboat for myself.
I've been looking for a shallow draft boat for some time now. And while I am tight on funds. You never know when things can change, and I like to plan for the future.
Near where I live, we have a river that for a long time was concidered basically a sewage canal. And for all intensive purposes dead. Things changed in the late 80's when for 3 consecutive years we had massive flooding. All this flooding pushed all the junk out of the river bed. Our states DNR took advantage of this and began a major restocking program as well as extensive restrictions on local communities and industry preventing future pollution.
What this means to me as a fisherman 20 years later. The fishing now is outstanding, if you can get to the sweet spots. During a year when there's average rain fall, many parts of the river is only 1-2' foot deep. The honey holes where the big walleye, sauger, pike, smallies, and even muskies hang out are mixed in areas that are difficult to get to. I've heard many horror stories on a local fishing forum that I belong to from guys trying to get to these spots with thier jon boats and using a trolling motor. Only to have thier trolling motors get beat up.
Then reicently I seen a show with guys running around the everglades in one of those airboats. And that's what made me start to think of building one of these. Further research on the net, and I found out about a class of boat described as "mini-airboats" which use small 10-30hp horizonal shaft eninges.
Why aluminium. Having asked about this on another forum, a person who also fishes a simlar type river in a different state, pointed out that had he gone with a wood or fiberglass hull, he'd of destroyed it by now. The aluminium has held up for him much better. So, now I'm on the hunt for plans for a mini airboat hull that uses aluminium. I have googled plans on the net, and have come up with only one comany that sells plans for a mini airboat. Those plans are for a wooden hulled boat. And from what I've read about this company's plans, they're a good idea for PLANNING, but not actually using thier plans for building a boat. I was hoping maybe someone on here may have already built an airboat or might know where I can get plans from for an aluminium hull.
03-04-2008, 11:07 PM
In 1992 the team took delivery of an 18' Panther flat bottom air boat and a 16' Avon rigid hull inflatable boat with a 90 horse power outboard motor. The air boat is housed at our new station 77 and the R.I.B. is housed at station 3 in Palo Alto.
The air boat is a 18'8" long, 8'4" wide, 9' high painted aluminum boat. AirboatThe bottom is covered by three 1/4" replaceable polymer sheets. The sheets allow the boat to easily slide over mud, grass, tulles, wood, and rocks with minimal damage. It is powered by a Chevy 350 V-8 (385h.p.). it has dual wood props for reduced noise and increased top end. The boat can achieve speeds of 35-40 mph on the water and over 50 mph on the mud.
03-05-2008, 12:25 PM
Have you ever looked at the plans for an airboat? I haven't done a search, but I suspect with the number of airboats used in the FL Everglades that there will be information available.
An airboat would make a lousy fishing platform for a number of reasons:
1. Noisy. Talk about pissing off your fellow fishermen.
2. Inefficient Propulsion at low speeds.
3. Tremendous above deck obstructions.
4. Maneuverability in tight spots--they slip steer vs having a skeg or a keel.
5. I could go on and on...
You're better off (for your intended use) looking to the Pacific Northwest where they have experience building heavy duty (Commercial) flat bottom aluminum skiffs. Drop a jet drive outboard (Yamaha makes one) on the back and you've got a tough, shallow draft, fishing boat that will go places a standard prop driven outboard won't go because of potential damage to the exposed prop.
I don't think you've done enough homework to be heading for the plans stage.
03-05-2008, 09:54 PM
Those big airboats are nice. I'm lookin more for a mini airboat. And yes I've been lookin for days for plans on the net. Other then here, http://www.airboatfun.com/ or Glenn-L I cannot find any plans. I even joined two airboat forums asking for other places.
I'm kind of partial to the 2 seater from airboat fun. These concidered mini airboats becuase they don't use huge engines. Mainly they use 2 cycle honda's, briggs/stratton, or modified snow mobile eninges. But most are 40hp or less in power. Hulls are typically from 8-12' long and anywhere from 4-7' wide.
These mini airboats are being built specifically for what I described. To gain acess to areas that normal boats can't get. Typically hauling 1-2 fishmen, gear, trolling motor and assosicated electronics.
There is a company that sells just the aluminum hulls, but they want like $1500 and that would need to be shipped from down south to chicago. That would really hurt the budget.
In the meantime, I'm gonna check out those NW boats that were suggested.
03-05-2008, 10:42 PM
Now, I know this isn't a boat...but...:p
03-06-2008, 12:03 AM
Aside from additional bracing, what is special about an airboat hull vs a typical johnboat? If you aren't putting a lot of thrust out, then I'd think you could strap a motor and prop to the back of one of them. They seem to sell pretty cheap and it wouldn't cost much to put a piece of poly-something on the bottom to protect it.
I do agree that even a small motor would make a lot of racket. I don't think I'd want to be fishing with one of them around. Fun? Sure! Fishing? I don't think so.
03-06-2008, 12:04 AM
Actually, you could make your pontoons and put them in place of Hotfoots tires. Then you could steer! ;)
03-06-2008, 01:13 AM
I have a Jon boat made by Lowe, they call it a "big jon" and it's 19' long X 7' wide, many of my friends said it would good with an airplane engine on it,, airboat style. mine looks like this in the link
something to consider, there must be some for sale near you.
03-06-2008, 09:32 PM
Yes, both myself and other's have asked about using a jon boat. But to keep in the mini class or smaller engines, you want to have a hull that's around 8-12' long. That one boat is 19' long right? That's why it would require a car engine, or small plane engine to get going.
The smaller jon boats don't have the width to get up on plane as a wider boat does.
Word about noise and fishing. Yes a 2 cycle motor is gonna be like fishing next to a lawn mower. NOT GOOD, that's why once you find a deep hole with your depth dectector, you shut down the prop motor and then drop your trolling motor down into the safer much deeper hole. Or you can just drop anchor and cast into the hole and use no motor.
With advice I've recieved from the two airboat forums I'm on, I've decided to go ahead and order the plans from airboat fun. Their basic concept is using 1"x1" framing covered with 1/4" plywood which is reinforced with fiberglass. This is a deck over design, so your deck would also be plywood as well. Basically you're building a large sealed box and one end has a slight angle to it so it can cut through the water. Admittedly building a hull from wood will be heavier then if it can be done in aluminum.
I've seen pictures of one of these boats being made. From what I can tell the framing looks to be 12" on center going both ways. The builder did add plywood between the bottom and top frames, I sappose for added support.
I'm just curious, and this is where I could use some suggestions. If the plans can be converted to using aluminum. Still using 1"x1" sqaure tube for frame. Would I even need a complete deck over? The aluminum would surely be stronger then fiber glass reinforced wood. Do a deck area where the motor is mounted in the stern and do another deck area in the front for live well and perhaps some storage. along the sides I can build some boxes for rod holders and stuff. What thickness aluminium sheet (and type) would be suggested?
04-04-2008, 10:27 AM
I just saw this thread, but....
The way you want to build an airboat hull is take a wide sheet of aluminum, cut the rake and nose out, then bend the sheet to form the sides. You'll need a press, because you'll need to build it from at least .125 gauge 5052 ot 5086
Then you weld the ribs in the bottom from the bow to the stern instead of across, so that when you hit stumps, etc. it won't crease the bottom across the width of the boat in front of a rib creating a "hook" in the hull. If it dents it will just dent if the ribs are lengthwise, but won't cause a hook. "Hooks" rob you of performance and the hull won't last very long or eventually won't plane.
And FYI - lower horsepower airboats aren't very good. I've seen a bunch of the "mini" airboats and was not impressed.
If you want something that runs shallow water under 50hp you want one of these on the back of a jon boat: www.prodriveoutboards.com
You'll need to boat decked over. If the sides are low you'll take on water and sink it. Usually take on water in an airboat over the transom because when you push up over something like a clump of grass, as the bow is lifted the transom goes down and that is also where the engine weight is sitting. And then you are sunk. I would deck the whole thing over just to be safe.
A common saying amongst the airboat crowd is "if you haven't sunk your airboat yet, you will."
04-04-2008, 12:21 PM
? The aluminum would surely be stronger then fiber glass reinforced wood.
I wouldn't bet on it myself, unless you used some pretty heavy aluminum. I wouldn't use fiberglass resin though. 2-part epoxy resin is alot better, stronger, doesn't degrade. Polyester resin will get brittle over time. Fiberlass cloth and epoxy resin laid over some 3/8 or 1/2" plywood is unbelievably strong. It won't dent or rip like aluminum sheet either.
Have you looked at the outboards made for shallow water? I think one company is called GoDevil or something like that. Swamp motors are unreal, I've seen guys go over beaver dams with them.
04-05-2008, 12:47 PM
Before you are set on doing an airboat look into mud motors, such as Prodrive,
Mudbuddy, Godevil, Beaver tail, and Scavenger.
You can get some good info for airboats from bowfishing forums also
http://www.dixiebowfishing.com/boat.htm building their own boat
10-28-2012, 07:39 AM
Am a new member and have read your threads with interest.
Am a boat runner for pleasure on the river Ganga in Northern India. Have old Jhonson sea horse OBMS and a flat bottom steel boat around 20', self made.
Want to make a new one, either an air boat or a water jet[ though i browsed the pro-drive motor with interest].
The river runs at varying depths, over seasons and a significant sandy delta, spanning 1-3 miles, at average currents around 3-4 mph.Depths can vary from 1' to 30' with the odd whirlpool and waves upto 2-3' in the monsoons.
Idea is pleasure, picnics,some wild boar etc.
Idea is also to be economical- fuel costs etc and yet fast enough to cover around 30 miles in a day.
Would appreciate some help, ideas and experienced advice.