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Author Topic: submersible motors  (Read 285 times)

jaymac

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submersible motors
« on: June 14, 2018, 04:30:15 PM »

Anyone  made a setup  to enable  making a  watertight motor  to fit a under a boat .Internal fit out of the question cannot find anything commercially available. Only required as a get me out of this situation
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KitS

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Re: submersible motors
« Reply #1 on: June 14, 2018, 04:57:13 PM »

Funny you should ask that.  :-)

I was thinking just the other day that a modern brushless motor ought to be able to run submerged as it has no electric contacts to short out. My thoughts were triggered by thinking of an outboard with the motor hidden in a fairing at the bottom of the shaft, but it might also work for a modern propulser pod as used on monster cruise ships etc.

What do our motor experts think about such ideas please?
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Regards
Kit

richardabeattie

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Re: submersible motors
« Reply #2 on: June 14, 2018, 05:00:44 PM »

Small pond pumps might do.
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richardabeattie

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Re: submersible motors
« Reply #3 on: June 14, 2018, 05:01:24 PM »

or maybe not - they usually run on 240V!
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Hotglove

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Re: submersible motors
« Reply #4 on: June 14, 2018, 05:19:28 PM »

Wandering lead and thick rubber gloves? Possibly duck or goose for dinner?
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Hotglove

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Re: submersible motors
« Reply #5 on: June 14, 2018, 05:28:22 PM »

Seriously, how big is the boat, what kind of speed required? Possibly use an off-the-peg submersible? Batteries in boat or batteries in unit? just propulsion or steering as well? Interesting thoughts.
I recently bought some very small but amazingly powerful magnets, it crossed my mind that it would be possible to use them as a drive system by having two flat rotors, each with 3 magnets attached one inside and one outside of a waterproof casing thus doing away with a shaft and seal.
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steamboat66

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Re: submersible motors
« Reply #6 on: June 14, 2018, 05:28:39 PM »

a brushless will be fine. if the three wires are generous, then there isn't even the need to waterproof the connections as they will be above the waterline.
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Big Ada

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Re: submersible motors
« Reply #7 on: June 14, 2018, 06:56:42 PM »

Brushed Motors will run under water, that's how some people used to run in the brushes.

Len.
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jaymac

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Re: submersible motors
« Reply #8 on: June 14, 2018, 07:03:48 PM »

Thanks guys  brushless is a thought 
Hotglove  48'' Brig speed just enough to get home,  steering her own rudder I'd hope, commercial aint seen any other than the toy ones and one of them will barely move my airboat
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Tug Fanatic

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Re: submersible motors
« Reply #9 on: June 14, 2018, 07:07:40 PM »


The people who know about this are the ROV community - the underwater drones. The favoured motor at the moment is the Turnigy DST-700. They even use it in sea water. Recommended mods include epoxy coating the coils and perhaps replacing the ball bearings with plain bushings but a lot run them as standard. The big danger for the underwater seems to be pressure at depth forcing salt water into the ball races and some motor designs which have a nice gap between the bearings which can fill with water..


Have a read here:
http://www.homebuiltrovs.com/rovforum/viewforum.php?f=3


& here
http://svseeker.com/rov_thrurters.htm


Follow the links & it is all there.
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tonyH

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Re: submersible motors
« Reply #10 on: June 15, 2018, 09:03:53 PM »

I bought a couple of really cheap pond pumps from fleabay for a recent project The moving part of the pump is an iron core which rotates. The coils are in a sealed sleeve so there is zero contact between the electrickery and the water. They ran on 12volts.

I then bought the one below which shifts significant amounts of water(1100gal per hour) for just over 13.00Same system, totally sealed motor.I think they call them "magnetic" motors so if you look up centrifugal pumps you could find something useful.
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