DIY Airboat project

[Coyotes-R-Us]

You all have seen where we take the mud boat and what we do with it but now we want an airboat.
We just found an old VW bug air cooled 1600 cc motor $100 and it runs.
It should have 50/60 hp.
NOW what?
I think we want a 14' flat john hull of some kind.
We will keep the seating "In the hull" Not sitting up high like a lot of them.
The motor I think needs to be setting on the floor of the boat.
Belt driven to the prop.
NOW what kind/ size prop do I need? RPM?
We are hoping to be able to drive it across grass and dirt 20/30 yards to the water. It needs to carry 3 people 30/40 goose decoys, guns , ammo, and a dozen dead coyotes. We plan to use it on the ice as well as water. Use the partially frozen rivers and lakes as access in to some virgin coyote hunting country .

Anyone here with some hands on information ?

THANKS GUYS

 

[Coyotes-R-Us]

WOW been a long time since I did an up date sorry.
Still in the works but about ready for an under power water test .

At long last I have steering for the waterbug.
Still needs adjusting and cable tightening.
I'll get some pics and maybe a Video up this week.

 

[Coyotes-R-Us]

First water test.
Went ok but I did find I need some more tweaking
https://www.youtube.com/watch?v=RGSZIXDUaM4&feature=youtu.be

[video=youtube;RGSZIXDUaM4]https://www.youtube.com/watch?v=RGSZIXDUaM4&feature=youtu.be[/video]

 

[Coyotes-R-Us]

Well Dang!!!!
I have decided to give the snowmobile belt drive up...
I just don't have the RPM/HP to make it do what I want.
I can't get it to get up to a 1 to 1 ratio at 3000 rpm so I have to run
the bug motor up to closer to 4500rpm to get the prop in to the upper 2000 rpm range. When I do get it up there the belt slips a lot.
I got a shorter belt to see if there was a difference, much better but still not good.

I got two 32 tooth #50 chain sprockets , same chain I use on the top drive, with 1 3/16th hubs.
they go right on to the parts of the SNB drive that I had made.
With the hubs I can change the ratio if needed with only a sprocket.
with a two stage chain drive I'll have to run idler sprocket on both chains I suppose. I had to put a key way in the shafts, amazing what an angle grinder can do. It is a little les forgiving then a belt as far as alignment. Hope to hit the gas this weekend and see if I can blow some dirt/gravel.

 

[PrairieHunter]

Interested to see how this works.

 

[mikieb]

what a cool idea.... and a fun project...


If I was doing it.... it would generate a large pile of empty beer cans and an insurance claim at some point...


keep us updated... I want to see this.... I want to see it work...

 

[huronmtns]

I am following along on this thread as well. My gut instincts have a feeling that switching to direct chain drive is not going to end well. Years ago I did some research on building an ultralight aircraft. There was a lot of content in that research that discussed the harmony between the prop and the engine. Ultra lights use belts because the belt will allow some slippage for the differences in harmony. I'm not real sure a 50 chain will have enough strength and endurance to have a reliable outcome. I suspect vibration will eventually eat up the driveline. I also hope nobody gets hurt caused by the amount of energy released when the failure occurs.

 

[Coyotes-R-Us]

I am following along on this thread as well. My gut instincts have a feeling that switching to direct chain drive is not going to end well. Years ago I did some research on building an ultralight aircraft. There was a lot of content in that research that discussed the harmony between the prop and the engine. Ultra lights use belts because the belt will allow some slippage for the differences in harmony. I'm not real sure a 50 chain will have enough strength and endurance to have a reliable outcome. I suspect vibration will eventually eat up the driveline. I also hope nobody gets hurt caused by the amount of energy released when the failure occurs.

Well that's reassuring..
Most VW prop drives are Direct drive right to the crankshaft on mini airboat set ups.
And most are on the front/ generator end of the motor. Some have gear or splined belt reductions.
I'm using the transition end and the belt ( now chain ) set up which is two stage, one from the flywheel end of the crank
to the secondary clutch shaft then to the prop with a separate chain.
The chain supplier( https://www.rollerchain4less.com/ ) thinks the #50 stainless chain will work for my application, all things lined up and well balanced