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Need Help With Home Preject

  1. Aug 22, 2009 #1
    Help Required On Home Project
    Hi Everyone,

    Im new to the forum, & I am hoping you maybe be able to help/guide me on a home project but firstly,

    ...Im 22,currently studying Pharmaceutical Chemistry & an avid rec & tech diver.

    ...my project is simply (or maybe not) to build a "scooter" or for its technical term, DPV, Diver Propulsion Vehicle which is a underwater propulsion system.
    examples attached above.

    My plan thus far is to use mains gas pipe with is plastic, approx 25mm (1inch) thick, which is rated to 10bar (147psi). I would rebate this like a tongue & groove setup so three o-rings can sit there, use loop latches to seal the two body pieces together. To achieve this I have located a large lathe. The o-rings will be x-ring which will trap air & thus seal better.

    I have big 12v batteries for the power side of things that I can rig up to 24v etc

    For the electrical set-up I will run a wire through the housing into a handle which will be for holding onto while using the DPV, fill this handle with electrical potting compound to waterproof is with a magnetic reed switch for stop/start with the magnet stitched into a diving glove on my hand. So basically when I grab the handle, the magnet will cause the reed switch to closes & off the DPV will go.

    Now is where Im confused, motors! Ive been advised to use a DC brushless motor but alot of models use sealed trolling motors but Im lost as of which one's because of the sheer choice of motors.any help would be great.

    From info I can gather the motor needs to have a RPM of 10,000 - 12,000.

    Next is the shaft & how to seal it for the water. Its be suggested to use a rifled shaft so that when the DPV is running the water will be pushed out constantly but what about when the DPV is not running.any help here would also be great.

    The propeller will be plastic, some commerically available units have metal blades but I think plastic would be better for safety in case someone got a limb into the prop then the blades would break as appose to chop limb off.

    So any help will be greatly appericated on the issues I outlined above & if you have another ideas to improve please say so.

  2. jcsd
  3. Aug 22, 2009 #2


    User Avatar
    Gold Member

    Welcome to PF, Ian.
    It might be to your benefit to use the forum search function to look up ROV's. There was a long and detailed discussion about motors, shaft sealing, etc. a couple of years ago. Although it was a remote-controlled sub rather than a scooter, I think that most of it would apply to your situation.
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