Hello I seen where you told some one you know how to build aluminum hulls. I got a few questions for you. about how much would it cost to build a 10x5.5 hull? Do you know a place to get the metal from? what all tools would I need to build the hull? Could you build a hull for me and i pay you? If so how much. The reason that i was going to go with a wood and glass hull is I can build thing from wood and I got a friend that works for pro line boat that can do the glass work for me. Thanks for the help. It will be a few weeks before i can get home to start working on my mini. I still have a lot of stuff to figure out 1 more question I am going to use a 1990 Arctic cat 440 its max rpm from what i can find is 7800rpm, what reduction ratio should i go with? sorry about all the question but it seem like you know what your talking about when it come to these minis thanks josh
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goldhunter_2
- Thread starter josh_2562
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goldhunter_2
Well-known member
7800 rpm I assume you are just using stock elec box (cdi) you are going to want about 2.5 or 2.6 to one ratio reduction
aluminum prices and your material list will very depending on the construction type of the hull example weld vs rivets or deck over vs open hull. also the alloys will be different and available sheet size depending on what your wanting I'll Pm you my number and can help answer that better on the phone then typing
aluminum prices and your material list will very depending on the construction type of the hull example weld vs rivets or deck over vs open hull. also the alloys will be different and available sheet size depending on what your wanting I'll Pm you my number and can help answer that better on the phone then typing
I can't call you right now I'm in France working and it about 2.50 a min to call the u.s does that 7800 rpm sound about right for a max rpm on a 440. I will be using all the stock parts for now. what would be a good cruising rpm for this engine I have a msd box I think I could use to put a rev limiter on it. If I build a aluminum hull I would have to rivet it. I would want a open deck with some thing to stand on the front to fish from. Thanks for the help Josh
goldhunter_2":2gqc8vx3 said:
goldhunter_2
Well-known member
oh ok ya that may be a long distance call :lol:
7800 rpm sounds on the high side for stock rev limiter to me but a after market one it may be about right for that engine, doesn't matter either way use what you have you just need to know the rpm to figure the reduction
open hull deep sides and a casting deck riveted yo could use 7075 aluminum alloy basic tools needed would be kelcos, aircraft rivets , rivet gun and block, metal saw , drill,and lots of time . make a drawing of the hull you have in mind and I'll figure you a material list up
7800 rpm sounds on the high side for stock rev limiter to me but a after market one it may be about right for that engine, doesn't matter either way use what you have you just need to know the rpm to figure the reduction
open hull deep sides and a casting deck riveted yo could use 7075 aluminum alloy basic tools needed would be kelcos, aircraft rivets , rivet gun and block, metal saw , drill,and lots of time . make a drawing of the hull you have in mind and I'll figure you a material list up
goldhunter_2
Well-known member
I'll work up a material list later tonight and pm it to you.
that's about 4'x8' or 10' I figure that material and a 5' flat bottom with 6' gunnel's by 10 also should be about the same
that's about 4'x8' or 10' I figure that material and a 5' flat bottom with 6' gunnel's by 10 also should be about the same
goldhunter_2
Well-known member
Josh,
sorry it took so long to get back with you on this . I figured a material list for two welded hulls that would take a beating (if I used it is how I think about it) if you want to go riveted hulls you can us a .30-.40 thickness and replace the 5052 or 5086 sheets with 7075 sheets material don't including welding supplies or rivets and are for 3/4 deck hulls 3' front and back decks
1) 4'x10' x 8" inches deep box hull like show in the other post pictures
5052/5086 4x12 sheet QTY 2 (one .125 = 83.52lbs and one .90 = 60lbs)
6061 T-bar 1.5"x20' sticks QTY 4 14 lbs each (56 lbs)
6061 1" round 20' stick QTY 1 12 lbs
6061 .125 flat 20' stick QTY 1 4.5 lbs
you would have 3-5 lbs of wire weight also rivets would be more
2) 6'x10' x8" (or 10")deep round side hull would have 5' flat bottom 6' gunnels 4.5'
wide bow 3/4 deck (3' front and rear decks)
5052/5086 5x12 sheet QTY 2 (one .125 = 104.4 lbs and one .90= 75 lbs)
6061 T-bar 1.5"x20' sticks QTY 4 14 lbs each (56 lbs)
6061 1" round 20' stick QTY 1 12 lbs
6061 .125 flat 20' stick QTY 1 4.5 lbs
Bend time on large press 1-2 hours
you would have 3-5 lbs of wire weight also rivets would be more
besides for the sheet alloy the materials will remain about the same weather you decide to build it with rivets or welding except for the sheet alloy
sorry it took so long to get back with you on this . I figured a material list for two welded hulls that would take a beating (if I used it is how I think about it) if you want to go riveted hulls you can us a .30-.40 thickness and replace the 5052 or 5086 sheets with 7075 sheets material don't including welding supplies or rivets and are for 3/4 deck hulls 3' front and back decks
1) 4'x10' x 8" inches deep box hull like show in the other post pictures
5052/5086 4x12 sheet QTY 2 (one .125 = 83.52lbs and one .90 = 60lbs)
6061 T-bar 1.5"x20' sticks QTY 4 14 lbs each (56 lbs)
6061 1" round 20' stick QTY 1 12 lbs
6061 .125 flat 20' stick QTY 1 4.5 lbs
you would have 3-5 lbs of wire weight also rivets would be more
2) 6'x10' x8" (or 10")deep round side hull would have 5' flat bottom 6' gunnels 4.5'
wide bow 3/4 deck (3' front and rear decks)
5052/5086 5x12 sheet QTY 2 (one .125 = 104.4 lbs and one .90= 75 lbs)
6061 T-bar 1.5"x20' sticks QTY 4 14 lbs each (56 lbs)
6061 1" round 20' stick QTY 1 12 lbs
6061 .125 flat 20' stick QTY 1 4.5 lbs
Bend time on large press 1-2 hours
you would have 3-5 lbs of wire weight also rivets would be more
besides for the sheet alloy the materials will remain about the same weather you decide to build it with rivets or welding except for the sheet alloy
Josh, 7800 rpm sounds real high to me. Two stroke engines can spin those kinds of rpm's, but not all the time, and you won't be there all the time.
Try to find out at what rpm your engine makes max. horsepower ..... that's what you'll need to determine your reduction ratio and prop length.
As an example, I have a 250cc Zenoah ultralight engine. It makes it's max. power at 5400 rpm. It will spin faster, but why would you want too ? Engine wear will go up and reliability will go down, and for nothing ..... no gain in push.
With a little experimentation I found out that it will spin a 42 X 28 prop DD up to 5400 rpm, and with a 2.5-1 redrive, a 54 X 26.
Both are both the sweet spot for the engine and the prop.
Do an internet search for the P-ponk prop speed calculator. It's a very neat little tool for helping you find the tip speed for different lengths of props, and you never want to overspeed one.
Try to find out at what rpm your engine makes max. horsepower ..... that's what you'll need to determine your reduction ratio and prop length.
As an example, I have a 250cc Zenoah ultralight engine. It makes it's max. power at 5400 rpm. It will spin faster, but why would you want too ? Engine wear will go up and reliability will go down, and for nothing ..... no gain in push.
With a little experimentation I found out that it will spin a 42 X 28 prop DD up to 5400 rpm, and with a 2.5-1 redrive, a 54 X 26.
Both are both the sweet spot for the engine and the prop.
Do an internet search for the P-ponk prop speed calculator. It's a very neat little tool for helping you find the tip speed for different lengths of props, and you never want to overspeed one.
goldhunter_2":13zu748g said:
Thanks for take the time to put these together for me. Do you know of a place to get the metal Florida at a good price? I found a place on the web and it about $400 a sheet is that about right? If so I'm not sure I want to spend that much to build a mini hull. If i did the welded hull i would have to pay some one to weld it for me. I don't have a welder for aluminum. thanks for the help Josh
goldhunter_2
Well-known member
400 hundred a sheet maybe for 7075 stuff but still think that is pretty high. the 5052 and 5086 stuff should be closer to 200 and 300 max a sheet. you just have to check around on price I have gotten material for one boat at a shop near by then a week later for the next boat it was cheaper to go to Miami and get the metal. some times a local shop will give decent prices but most the time they mark it way up especially if there not used to handling aluminum
grant
Well-known member
I run an O540 290 hp on a 10' x 7' hull made out of 0.90 6061, it is 18 years old and has had the s hit worked out of it! So don't take this the wrong way, but I would not use 1.25 on a mini and I would stay away from 5052, its just too soft!
My thoughts would be more on the line of rivited 6061 or 7075 ( 6061 preferably as it is easier to get 90 deg bends and it will work harden to nearly as good as 7075, in my opinion it has better wear characteristics ) 0.90 max 3 to 5 stringers and they could be out of angle to save more weight over T bar. The top chines, the bow cap and possibly the stern could be broke and braced strategically for weight savings.
I could post some better closeup pics of one of my 4' x 8' pole boats to give y'all some ideas it ya like!
My thoughts would be more on the line of rivited 6061 or 7075 ( 6061 preferably as it is easier to get 90 deg bends and it will work harden to nearly as good as 7075, in my opinion it has better wear characteristics ) 0.90 max 3 to 5 stringers and they could be out of angle to save more weight over T bar. The top chines, the bow cap and possibly the stern could be broke and braced strategically for weight savings.
I could post some better closeup pics of one of my 4' x 8' pole boats to give y'all some ideas it ya like!
jpatter123
Well-known member
Josh where you at in Florida? I know of a few places on the west coast that deliver. Seems to me that price your getting online is high. I checked online for the DOM we used for our metal works and the prices were 250% higher then I could get it locally for. Some towns aluminum is hard to come by. I had a hell of a time locally trying to find some thick wall aluminum tubing.
goldhunter_2
Well-known member
grant is right you could use a .90 all the way through I just figured heavy duty like I was going to build for my self that is way I say .125 for the flat bottom area the weight difference compared to the durability there is no question IMHO. the .90 has more flex to it , in my opinion thus requiring more support.
I notice in the airboat community it seem to be a standard to use the 7075 and not to disagree but I have built many a boat out of the 5052 and 5086 that hold up really well . the phrase 'hold my beer and watch this" or "give it H***" don't even come close to what I put some of them hull through
that video in my gallery was a .90 5052 hull and that held up to crossing and stumps etc etc etc
I also believe I could punch a hole in a 7075 hull quicker then a 5052 hull :lol:
I notice in the airboat community it seem to be a standard to use the 7075 and not to disagree but I have built many a boat out of the 5052 and 5086 that hold up really well . the phrase 'hold my beer and watch this" or "give it H***" don't even come close to what I put some of them hull through
that video in my gallery was a .90 5052 hull and that held up to crossing and stumps etc etc etcI also believe I could punch a hole in a 7075 hull quicker then a 5052 hull :lol:
jpatter123
Well-known member
my aluminum supplier for soffits, gutters etc sells industrial aluminum in tampa and their prices were really really good. I couldn't use them even though I do 100's of thousands of dollars a year through them because you have to order so much for a delivery but if you wanna go pick it up there I could give you their number. Just lemme know.
grant
Well-known member
If you are gonna build an airboat out of 5052 or 5086 or construction grade aluminum, then you most probably will need to use 1.25. These materials do not compare to aircraft grade material and will need to be thicker.
The pole boats I made out of 5052 have dents and loose rivets because it is to soft an alloy to take even the rigors of alligator hunting the way I do it. 5086 is the min I would use and I think you would be advise to go 1.25 if you want to pound ground!
6061 or 7075 aircraft grade will stand the abuse!
The pole boats I made out of 5052 have dents and loose rivets because it is to soft an alloy to take even the rigors of alligator hunting the way I do it. 5086 is the min I would use and I think you would be advise to go 1.25 if you want to pound ground!
6061 or 7075 aircraft grade will stand the abuse!
Josh,
FYI
I've been airboating with Grant for a couple of years now and I have seen his airboating techniques first hand. The man expects performance.
He's been around the proverbial airboating block and has experimented with all types of hulls, engines, materials, and configurations. I'll say it again, the man expects performance and I value his experienced opinion. It just might save you some time, money, and aggravation.
Spend your time and money wisely on the front end, and it will save you time, money, and aggravation in the long run.
FYI
I've been airboating with Grant for a couple of years now and I have seen his airboating techniques first hand. The man expects performance.
He's been around the proverbial airboating block and has experimented with all types of hulls, engines, materials, and configurations. I'll say it again, the man expects performance and I value his experienced opinion. It just might save you some time, money, and aggravation.
Spend your time and money wisely on the front end, and it will save you time, money, and aggravation in the long run.