Build a Diver Propulsion Vehicle with Help from Experts | Home Project Guide

[IanK]

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.
http://www.torpedodpv.com/
http://www.silent-submersion.com/pictures/index.htm
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 I am confused, motors! I've been advised to use a DC brushless motor but a lot of models use sealed trolling motors but I am 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.

Thanks,
Ian

 

[Danger]

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.

 

[oswaler]

Dear Ian,

Thank you for reaching out to our forum for help with your home project. As a fellow scientist and avid diver, I am excited to hear about your plans to build a Diver Propulsion Vehicle (DPV). This is a challenging and ambitious project, and I am happy to offer some guidance and suggestions.

Firstly, I commend you for your thorough research and planning so far. It seems like you have a good understanding of the materials and components that you will need for your DPV. In terms of the main body of the vehicle, using a plastic mains gas pipe with a tongue and groove setup and o-rings for sealing sounds like a viable option. However, I would recommend consulting with a materials engineer or diving equipment expert to ensure the safety and durability of your design.

For the electrical setup, your plan to use 12v batteries and a magnetic reed switch for stop/start is a good idea. However, I would also suggest incorporating a safety switch or emergency shut-off in case of any malfunctions. As for the motor, a DC brushless motor would be a suitable choice for its efficiency and power. It is important to choose a motor with the correct RPM range and torque for your DPV's size and weight. I would recommend consulting with a motor specialist or researching more specific models for your project.

Regarding the shaft and propeller, using a rifled shaft to constantly push water out while the DPV is running is a good idea. However, you will also need to consider how to seal the shaft when the DPV is not in use. This could be achieved with a waterproof seal or by incorporating a mechanism to close off the shaft when the DPV is turned off. For the propeller, using a plastic one for safety is a wise choice. I would also suggest considering the size and shape of the blades for optimal propulsion and maneuverability.

Overall, it seems like you have a solid plan for your DPV project. I would recommend seeking advice and guidance from diving equipment experts or engineers to ensure the safety and success of your design. Also, don't be afraid to experiment and make modifications as needed. I wish you the best of luck in your project and happy diving!

Sincerely,