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Ice boat build help

Ecmart

Member
Hi all, I'm lookin at building a Ice boat and hoping someone can point me in the right direction. Any guys up north with experience? Im planning on something around 14' and even considering doing a custom aluminum hull. Thanks!
 
I've owned three airboats. All of them have been have been reinforced for ice. But I have only had one of the boats "built" for me. The other two I have bought used. When I had this last one built three years ago with Diamondback, I know we added extra T bars to reinforce the hull, thicker polymer and ran it up the side a little higher than a Florida boat. I also know some have added a thicker side walls in the construction as well.

Almost all of the airboats in Utah run ice since half of our duck hunting season is during winter and ice fishing as well.
Two thoughts I would chime in as you do this build.
-No matter how you do it, an ice hull adds weight so calculate that into your engine HP, prop and gear reduction so you don't end up underpowered.
-No ice hull is bullet proof. Some of the worst days for air boating on your hull are the early or late season ice days. When the ice is thin enough that you break thru when you stop or go at slower speeds is when you can still bend/damage your boat.

I would reach out to Diamondback or Hamant. DB sells quite a few boats in Utah and I know several who have had Hamant build their hull.
I don't do facebook, but there is a Utah Airboat Association facebook page. I would join that group and post this same question. About 70 percent of the boats in Utah are home builds. I'm sure you could get more specific help from people who have been building their own boats here in Utah.

Good luck with the build!
 
This is exactly what I was looking for, thank you Pato! The purpose of the boat is specifically for ice fishing on bad ice, or just getting rid of cabin fever during the winter. Speed is secondary to me, but I am looking for 40 MPH with two people and some gear, but I don't know, maybe that's fast for an ice boat. I was originally planning on an aluminum Jon boat but now, I am more looking at doing the hull inhouse or ordering something. We have the ability to build the entire hull and was curious about a sorta tunnel hull to allow hatches in the floor. Something 60" wide on the bottom, with just a wide enough tunnel to allow 8-9" hatches in the center. Maybe 2" tunnel? I really don't know just kicking around some ideas to accommodate the boats purpose. I really appreciate you responding. What engines have you used? I've been looking at Rotax and at some older jet ski engines. I am trying to find a good balance between weight and HP.
 
Well, I'm not Rick, but I am another casual observer . . .

The previous poster who has the exact experience you were asking for, tells you . . .
No matter how you do it, an ice hull adds weight so calculate that into your engine HP, prop and gear reduction so you don't end up under powered.
You seem to conveniently over-look what that means. NOTE AND UNDERSTAND the man telling you
this is currently running a 427 with a blower AND a 2.55 ratio gearbox AND is turning an 82" 5 blade prop ! !

Your response was "I've been looking at Rotax and at some older jet ski engines".
Your first post read like you were somewhat knowledgeable about this subject matter. Your second post reads like that isn't the case.

A five foot wide airboat with an engine like you've been looking for would be perfect for "just getting rid of cabin fever during the winter.", as long as you were intending to do that in the pasture behind the house. However, if "The purpose of the boat is specifically for ice fishing on bad ice", you would likely save a lot of money and stay a lot warmer by just sticking with the jon boat.

When Pato said what he did above, the implication was to first build the hull as it needs to be and THEN
get enough power to enable you to operate it safe and effectively. This implication seems to have completely eluded you.
You simply can not start with with an under-powered engine and then shrink the boat to match the lack of power.
The Laws of Physics aren't variable and don't much give a damn about a man's good intent or budget.

I suggest you do exactly as Pato suggested and call/talk to Diamond Back and/or Hammat about building you an ice hull and what power they recommend. I would bet that you would find that enlightening.

Nothing wrong with asking questions, but you may be better served to first figure out the [SEARCH] function and do some reading as there is already a lot here about building an ice capable hull and their characteristics.
 
Thanks Deano! Some of that is helpful and yes, Patos response was excellent. However I did not overlook what he said, I actually took notes concerning what his set up is and I have been looking into pros and cons of hull styles, weight savings, engines, props, whatever I can soak up . I will be speaking to Diamondback, and a couple others. As for airboat knowledge, I know absolutely nothing about airboats, and I am completely ignorant on the matter. Can you elaborate on your response/thoughts to my second post, ? Is 40 mph unrealistic, issues with building my own hull or specifically the tunnel? What are the issues with running a rotax engine, specifically an 850 Etec?
 
Three more things.

1-You need/want polymer on almost any airboat, but specifically on an ice boat. IMO you won't ever be able to have an airboat that has "latches" in the floor to fish thru. We always haul an ice tent, full size grill and coolers and only go when the ice is good to fish on, not from the boat.

2-Build the boat to run in water. The reason I say this is it takes very little to run on straight ice. Whatever your max speed is on water, your max speed on clean ice (no snow on top, just ice) is 3x your water number. Never tested that above claim, because anything on ice is scary and I try to never go above 25 on clean ice. I can basically go 25 mph just letting the boat idle or between idle and 1,500rpm. Going 40mph on ice literally takes 400 yards to stop once you pull back on the throttle. Hence, you don't do it.

3-Length and width are your friend on ice. My fav ice boat of the three was a home built hull/boat that I bought. It was 8.5x18 and had a 383 stroker on it. Slightly underpowered a touch for water conditions, but great on ice. Longer/wider boats will more stable, but require more HP in water. About 30% of our boats in Utah are "Florida" style boats, 70% are Alaska/Utah style boats. If ice is your priority or a must I would suggest an Alaska style boat. Not only does it give you a cab to hide behind in the cold, IMO they are safer on the ice. The reason is the cab adds weight out front as well as lowering your center of gravity with you and your crew. If you get going sideways on ice...a lower center of gravity is ideal IMO.
 
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OK. One more add.

-There is a boat in Florida that has my same exact engine, blower, prop and gear reduction. His boat is a 14ft Florida style boat.
Mine is a 16ft Utah/Alaska style boat. So I have two extra feet, a cab, and the added weight of an ice hull. But the rest is identical.
His max speed is 85mph and mine is 65mph. Which brings me to my point. Not sure where you are located, but in addition to added weight, you may need to factor in elevation. A general statement in the HP world is for every 1,000 ft of elevation above sea level you subtract
3-3.5% of your HP. In Utah where we hunt, we run about 4,300ft above sea level. So right out of the chute, I have 12-15% less power than the guy in Florida with my exact same set up. Calculate in elevation (if needed) when reading on forums and seeking advice. If someone told me their boat ran 40mph max in Florida, the max speed in Utah would be less.

As Deano recommended, do some searches and reading on this site. So many great threads with info. When I was building my third boat, I still spent hours on this site reading and learning even though I had owned two other boats with 20+ years of experience.
I would spend some time reading up on engines, gear reduction, prop and prop pitch. Terms like "cruising speed", "efficiency" and "rpm" as it relates to your build will be as or more important than max speed.

Lots of great people and info on this site.
 
Hi all, I'm lookin at building a Ice boat and hoping someone can point me in the right direction. Any guys up north with experience? Im planning on something around 14' and even considering doing a custom aluminum hull. Thanks!
I have no experience with the other hull manufacturers mentioned, but you may want to investigate Alumitech as a candidate. I live on the Minnesota/Canada border and in my opinion this is the best ice hull operating here. Another recommendation would be to avoid the Rotax unless you are planning to never break through the ice, or run on water. In these conditions horsepower is king, and you'll need a whole lot more on a 14 ft. hull to climb out of the ice. I'm running a 0470 gpu. on a 14 x 7 hull and would not want any less to safely operate in all conditions. Especially with any kind of load.
 
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