Amphibious ATV

About using jet ski motors to power small boats

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sploople
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Amphibious ATV

Postby sploople » Mon Oct 18, 2010 2:00 pm

New here! A Google search brought me to this forum, and I would love some input on a little project some friends and I are discussing.

We have our ATV floating, but not very maneuverable. We have discussed building out a tranny with an impeller drive that could be shifted into for water use.

These are the design parameters:

Loaded weight: 800 lbs.
Motor: 10hp
Desired speed: 10mph

Is this possible with only 10hp?

How heavy would the required impeller be?

What flow-rate impeller would be required?

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DaveLott
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Re: Amphibious ATV

Postby DaveLott » Mon Oct 18, 2010 3:34 pm

Ok, you have going to have to give us a lot more information. Let's start with some pictures of what you have done
Dave

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Dave Grason
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Re: Amphibious ATV

Postby Dave Grason » Mon Oct 18, 2010 3:58 pm

This sounds like something the folks on "Mythbusters" would do. It also sounds like a lot of fun. Who knows, you could be building the prototype for a new vehicle. Like Dave Lott, I'd like to see some photos as well. That would give us some more to work with.
Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

sploople
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Re: Amphibious ATV

Postby sploople » Mon Oct 18, 2010 4:01 pm

Thanks for the reply! Here is a picture of the vehicle. What other info do you need to tip me in the right direction?

Cheers

Image

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BruceDow
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Re: Amphibious ATV

Postby BruceDow » Mon Oct 18, 2010 5:03 pm

We always love a good intellectual challenge.

It is unlikely that you will get anywhere near 10 MPH. You will not be able to get that thing planing, so you will need to be satisfied with "displacement speed". that is 1.3 X sqare root (length). so if your "boat" is nine feet long, the fastest you can go is 1.3 x 3. Let's call that 4 mph.

This might give you some inspiration... It is long, but hilarious... well worth the 10 minutes to watch it.

http://www.youtube.com/watch?v=KzxuEOxYSLE

Please report back with your own video!
Bruce.

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~~ To me - only my boat is not yet perfect. Everybody else's is to be admired for I know the path they have walked (Dave Lott, 2010) ~~
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sploople
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Re: Amphibious ATV

Postby sploople » Mon Oct 18, 2010 6:49 pm

Great video! I'm a big fan of Top Gear... hadn't seen that one yet.

Two questions:

1. Say we accepted 4MPH, where would I look to find specs on impellers that would tell me volumetric flow rate at a given RPM? We could use that value to calculate thrust, no?

2. Say we... umm.... made it a hovercraft... we still limited at 4MPH?

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Mr Hot Rod
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Re: Amphibious ATV

Postby Mr Hot Rod » Mon Oct 18, 2010 11:53 pm

Bruce Dow wrote:You will not be able to get that thing planing

Just by looking at it, I'd find a Glen-L plan with an LOA a bit longer than your vehicle's wheelbase (a Squirt ??). Trim a rectangular opening in the hull until it slips over your buggy. This will give you more boyancy (pontoons and a bow) and a planing surface (floorpan). If it's done properly, it won't affect the buggy's resale value if the project fails. The boat will be a total loss though :cry: An engine-mounted hydraulic pump could spin a retractable propeller shaft via a hydraulic motor. This would give you F-N-R. Increase power until it planes ...

We never said that this was going to be easy ! Good luck with your project !

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Re: Amphibious ATV

Postby Caber-Feidh » Sat Oct 23, 2010 8:59 pm

Thrust is a function of pressure in the bowl, and area of the nozzle outlet.

A jet pump would work, but for displacement speeds, I think I would almost lean toward a setup based on the design of the ww2 VW type 1-66 schwimmwagen
http://www.speedace.info/automotive_dir ... n_1943.jpg

A better shot of the drive line
http://en.wikipedia.org/wiki/File:VW_Schwimmwagen_3.jpg


Would be pretty simple to construct, for the most part. The original porsche design uses a sealed pivoting case containing an oil-bath and double column roller chain. I can see salvaging a final drive case from a snowmobile as an easy way around building the whole case from scratch.

Jet pumps don't like sand/gravel trees, sticks at all. Even trailering a mixed flow driven boat down a gravel road can do unbelievable $$ in damage to impeller, and wear ring. (not to mention shaft tail bearing) An axial flow would be better, but still, has to be disengaged, or the water-lubricated rear bearing is going to gall up in minutes.
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Cranky Badger
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Re: Amphibious ATV

Postby Cranky Badger » Sun Oct 24, 2010 7:15 pm

Just thinking along a bit of a different direction here...but what about using something like an automotive A/C compressor mounted on the engine as a PTO to drive a hydraulic motor which drives the prop ?

The clutch would allow you to engage/disengage the 'water drive' with the flick of a switch so you don't have much of a parasitic HP draw on the small engine.

The motor itself will run fine when submerged so you don't have to worry about sealing the shaft hole from the engine bay/passenger compartment.

I think the biggest single cost would probably be having a splined adapter machined so you can use stock props until you figure out the best size and pitch.
-Brian

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upspirate

Re: Amphibious ATV

Postby upspirate » Sun Oct 24, 2010 7:43 pm

How about just paddle type sand tires on the back and detachable blades for the front tires?

http://www.google.com/search?ie=UTF-8&o ... 430ac3503f

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Re: Amphibious ATV

Postby Scott » Thu May 26, 2011 12:52 pm

For a prop I would go for a composite prop since the blades are interchangeable if one were to hit some obstacle in the process.

Why do you only want to use 10hp?
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steve crawford
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Re: Amphibious ATV

Postby steve crawford » Thu May 26, 2011 7:31 pm


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Vlad
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Re: Amphibious ATV

Postby Vlad » Fri May 27, 2011 8:10 am

I love this type of ATV. Couple years ago I was very tempted to buy this one


Image


then decided against it. Very small engine, foreign made, customs/delivery hassles etc. Recently I was contacted again if I want improved version :)


http://www.youtube.com/watch?v=Uf5m2cKu0IU


sorry could not help on impeller. Your project looks nice I am sure you will get the jet right.
Squirt - planning stage

mark1992
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Re: Amphibious ATV

Postby mark1992 » Fri Aug 05, 2016 12:31 am

sploople wrote:New here! A Google search brought me to this forum, and I would love some input on a little project some friends and I are discussing.

We have our vegas atv tours floating, but not very maneuverable. We have discussed building out a tranny with an impeller drive that could be shifted into for water use.

These are the design parameters:

Loaded weight: 800 lbs.
Motor: 10hp
Desired speed: 10mph

Is this possible with only 10hp?

How heavy would the required impeller be?

What flow-rate impeller would be required?


I would like to suggest one thing to you. You using a power of 10 HP. So to utilized its power properly you have to make your ATV's frame some kind of light matel like aluminim because aluminim is light in weigh and have very good tensile strengh to bare any force or impact.


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