Just What You Need When the Chips are Down.........An Underwater Drill

William_H

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Ideal for drilling a hole in the hull then running in a tap so I can bolt a saddle to the under hull. I would then attach a rope and bucket
to my opposition,s hull before a race!!!!!!!!!!! from the dark side of olewill.
 

fisherman

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Ha, we used to race with Seagull outboards (there wasn't anything else, unless you count my brother's Aurora Aquajet, singularly useless). I would be hanging over the bow, if we were overtaken we would try to slot in behind to a) slipstream and b) turn off their fuel tap.
 

rogerthebodger

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Any pneumatic power tool will work OK under water and you don't even need a compressor just power it off your SCUBA cylinder. 1st stage regulator output is generally about 150psi which is OK for most pneumatic power tool. If using in sea water just wash in fresh water after use.

Now that may be an idea to power a small outboard rather than a battery drill.
 

fisherman

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Any pneumatic power tool will work OK under water and you don't even need a compressor just power it off your SCUBA cylinder. 1st stage regulator output is generally about 150psi which is OK for most pneumatic power tool. If using in sea water just wash in fresh water after use.

Now that may be an idea to power a small outboard rather than a battery drill.

So how far might you get using a diver's bottle with suitable delivery pipe and nozzle as a jet drive? Or even a petrol powered compressor? Jet drive can be more efficient than a prop.
 

rogerthebodger

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So how far might you get using a diver's bottle with suitable delivery pipe and nozzle as a jet drive? Or even a petrol powered compressor? Jet drive can be more efficient than a prop.

If the delivery pipe was connected direct to the cylinder I think at 3000psi it would spray the water every where any you would get very wet. Connected to the 1st stage output might work but IMHO you would still need very good control of the flow. Petrol powered compressor why not use a petrol powered outboard. Drill type outboard are very low noise which is what I want in a quite anchorage

The efficiency of a jet drive comes from the fact of high water flow low pressure. The type of jet drive you propose is high pressure low flow. not so efficient.
 

fisherman

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If the delivery pipe was connected direct to the cylinder I think at 3000psi it would spray the water every where any you would get very wet. Connected to the 1st stage output might work but IMHO you would still need very good control of the flow. Petrol powered compressor why not use a petrol powered outboard. Drill type outboard are very low noise which is what I want in a quite anchorage

The efficiency of a jet drive comes from the fact of high water flow low pressure. The type of jet drive you propose is high pressure low flow. not so efficient.
Merely opening the valve is akin to an explosion, there would have to be a suitable regulator.
 

William_H

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If the delivery pipe was connected direct to the cylinder I think at 3000psi it would spray the water every where any you would get very wet. Connected to the 1st stage output might work but IMHO you would still need very good control of the flow. Petrol powered compressor why not use a petrol powered outboard. Drill type outboard are very low noise which is what I want in a quite anchorage

The efficiency of a jet drive comes from the fact of high water flow low pressure. The type of jet drive you propose is high pressure low flow. not so efficient.
Yes a SCUBA tank has quite a large pressure in the bottle. Once I had one on my back in shallow water and asked a friend to check the valve was fully open. He loosened the clamp instead of the valve causing a huge leak of high pressure air. Certainly made bubbles. Quite alarming for me as I could not reach it and had to take the tank off my back. To get real eficiency from a SCUBA tank for propulsion I think you would need a pneumatic motor driving a large slow turning prop. As said it is all about coupling the energy to the water in an efficient (matching) way. olewill
 

rogerthebodger

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Yes last time I was in Durban I was playing with the electric outboard I knocked up from an old battery drill, a right angle drive and a old prop I had lying around. I worked very well and took me across the marina at about 1.5 to 1.9 kn depending on the head wind. I am now changing the right angle drive from 2 : 1 reduction to 2 : 1 increase as I feel the drill had plenty of power.

The use of scuba tank and air drill came from that and this thread. Now cone to think of it the air drill with a prop in the chuck connected to a scuba tank could be a c low cost scuba scooter. Now that's worth trying once the water heats up a bit.

BTW fire fighting breathing gear have the valve at the bottom where scuba is at the top, it is much easer to reach the bottom mounted vales that the scuba type. The pressure in fire fighting breathing gear I trained in was 300 bar where scuba is only 200 bar.
 
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Adamastor

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To get real eficiency from a SCUBA tank for propulsion I think you would need a pneumatic motor driving a large slow turning prop. As said it is all about coupling the energy to the water in an efficient (matching) way. olewill

Whilst we're faffing about with our eco-friendly stealth-outboards, why not run, say, a Stuart-Turner Compound Launch engine off compressed air, with a cardan shaft through a couple of CV joints to the powerhead spline of your outboard. That you could couple together with a little Muffett gearbox and have deathly-silent propulsion so you can enjoy the scrunchy noises the spectators make while they craft you tinfoil hats as you go past!
 
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