A dive scooter, or a submersible ducted fan used by divers, is not a new invention. They’ve been around for years, used by everyone from the villain of the week on Miami Vice to professional divers. Now that high-capacity Lipos, 3D printers, and powerful brushless motors are cheap, it was only a matter of time before someone built a DIY dive scooter. [Peter Sripol] is the man, and he also built a dive scooter, underwater pistol thing.
[Peter]’s dive scooter is almost entirely 3D printed. That includes the ducted fans/thrusters. The electronics are what you would expect from a grab bag from Hobby King and include two 2530 sized 400Kv motors from Avroto. These are massive motors made for massive quadcopters but they do seem to work just as well pulling a human underwater.
While this dive scooter was a marginal success, there were a few problems [Peter] had to work through. These were the lowest pitch propellers [Peter] has ever printed. To be fair, most of the props [Peter] has printed were used in air, not a fluid that’s hundreds of times denser. The electronics held up very well, considering the bath in salt water.
You can check out [Peter]’s video build and demo below.
19 thoughts on “The Almost Working, DIY Underwater Scooter Pistol Thing”
Hey, let’s not forget Thunderball!
A really good start – has anyone measured the pressure resistance of 3-D print surfaces? Given that they’re made of (hopefully) fused layers, I’d bet that there’s a bit of moisture that could get through the surfaces.
I am assuming one should apply some kind of rubberized coating on the outside surface, at the very least!
Could strengthen it with epoxy:
I wonder how well vacuum impregnation would work on prints.
Might as well just make fiberglass / micarta blades and parts at that point.
I had forgotten about micarta. Interesting what one can make using old denim and epoxy.
Provided the fusing is good, not much should get through. The worry I’d have is the structural integrity of the layers vs solid pieces reinforced with solid ribs or suitably filled interior spaces. There is a reason most stuff that can handle deeper water gets made from crazy materials in weird shapes and costs so much.
We have done quite a bit of testing on 3d printed custom pipe couplings, and in our experiments, we used 70% infill ABS with acetone vapor polish and rubber gaskets, and those parts stood up to about 2-3 bar of water pressure..
I recall that an ABS scuba regulator from a few months back on HAD had a big problem printed at 100% even from the pressure difference of inhalation to tripping the air release valve; so I suspect that it takes several coats of ABS/acetone goo to caulk this properly. Or perhaps don’t worry about pressure and just silicone or epoxy pot the connections and circuit board, not sure about a motor capsule though.
I think most FDM printing is akin to a screen door on a submarine without serious post processing.
This is a great project, well done! One thing that worries me is how the salty water will affect the motors since these are clearly not sealed. Sure there are no “contacts” out there but still… salty water is not good in contact with metals that may form galvanic piles.
Spray it down with RO or distilled water (or even regular tap water) after use and it’ll probably outlast the batteries life span. Can’t corrode if there’s no electric connection left by salt bridges.
This is the same guy that made an RC plane using KFC buckets!
As said I worry about the sealing of the motors. I like it.
windings can be epoxied, I’d worry about the bearings…
a lubricant weak to moisture or heat dynamics would kill it. Needs careful selection.
Some of those bigger hobby motors have replaceable bearings so just switch to cermics and its all good
Is it any better than slightly moving your legs though?
I think that you’ve got the wrong website to say that people should go out and exercise instead of making cool gadgets!
I wasn’t saying he should exercise I was saying that the pull can’t be much better than moving your legs a bit with flippers on.
Basically I wonder if it is worth having at all.
In the video he says ‘it does beat kicking, but a decent swimmer can probably go much faster than this’. So I guess that’s answered. However he does highlight that it’s fun, so you got that going for it.
Maybe you can utilize it for something, maybe to drag a line independently, or a small net to get junk out of the pool? It would just need to be able to keep going in a straight line when released to get some independent operation going, and that should be doable.
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