Homemade DPV

grandizer52

Has anyone made a DPV? I think this would be a great challenge also due to the creativity of rebreather divers.

decoweenie

IMHO, ot worth the time or money since it will cost more than buy a commercial one...

Having said that, this is the best effort of home-made DPV I have ever seen.

http://web.mac.com/hammanfamilydenta...Prototype.html

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Scuba_Vixen

It depends a lot on where the motivation is coming from.

If you go the DIY route to try to save money, Forget It, .... it ain't gonna happen that way. .... at least not for anything you'd want to depend on


If the motivation is to build the best scooter that can be built, cost not withstanding, then the link Phi posted is testament to that.


The concept of the DIY scooter has been around a long time and many have tried it......

There's 2 basic ways to go, the submersible trolling motor and the Tekna/Mako kort nozzle system.

Trolling motor seals are not designed for depth, so they are only suitable for shallow use.

The T/M kort nozzle setup uses a mechanical seal which works well, even past 100m. It's also a more efficient thruster design.

Real world testing has shown that propeller RPM in the 800 to 1200 range is most suitable to DPV use, so you need to setup your power train design with that in mind.

The Mako uses a purposely built, 8 pole - permanent magnet motor, that runs about 850 rpm in stock form. (SS and Gavin use a rewind that runs about 200 rpm more) ... Most such motors are designed for much higher rpm and need gear reduction, which adds weight and complexity and Noise.

Unless you just like DIY projects, the $$$ spent versus "level of usefulness" ratio is usually not very favorable compared to buying a good second hand unit.


All that not withstanding, here's a pic of an intrpid DIYer with a DIY scooter project built with about a $25 budget. It actually worked.



Darlene

Attached Images

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divetheworld

Ask Mr Routley about these from his site.....




The last two were there when I last called round.


Brent

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jaap

Is it electric?

I fully agree that a DIY DPV is a hard one, at least if it is going to be cheaper, reliable and capable of any depth. Abandoned my DIY DPV plans very early and bought a second hand Scubapro DPV for 400$ to play with instead.

But since tinkering and playing around is always fun I made a very DIY penumatic DPV. With a nozzel running either from a SCUBA-cylinder or a CO2-exstinguisher. Not very practical, not much range/speed and only for shallow playing. It sure was noisy and making bubbles...Will try to dig out some photos. Even thought about fitting a prop to a pneumatic tool...but I was not quite ready for the Darwin awards so that never happened.

grandizer52

So noones tried eather compressed air? or OTTO FUEL II? So far noone's come forth to say if they have tried to/attempted to...build one

plazma

I have opened a MotorGuide trolling motor and a ScubaPro UV scooter. They have the same kind of seals. The ScubaPro is specified down to 50m (IRC).
Does ScubaPro use Minnkota trolling motor parts for theit DPV?

MotorGuide trolling motor seal.

Scubapro UV scooter motor.

Scuba_Vixen

The one thing to keep in mind here is that Scuba Pro and the trolling motor maker are both owned by Johnson Outdoors.

Trolling motor seals in good shape seem to work pretty reliably to about 100' or a bit more. Most of the time.... Though that wasn't an original design criteria, it just sorta works out that way.

This is workable for recreational diving, but hardly suitable for the tech realm.

Filling the motor with oil is one method that's been tried to extend it's depth, but as it warms up, the oil expands and seeps out, then when it cools again, it creates a vacuum which wants to suck whatever is around, back inside. ...... Not good when it's been sitting out in the sun and you take it into the cooler water.

You'll notice also that the SP dpv is seldom ever mentioned in any serious dpv comparisons, and they didn't sell like hotcakes either.

It was really a case of SP trying to compete in a market where they didn't have to spend much money to develope a product. They got out of the venture, exactly what they put into it. .... Diddly Squatt



Darlene

jaap

My old SP SeaWing is rated to 70m. And yes I think the parts are maybe from Minnkota.

At least a new prop to SP is avaliable as a spare from Minnkota. They look identical.

Caves&Bunnies

OTTO FUEL???? Can't hide the fact that you're a Bubblehead anymore. Yeah I was a TM on Nuke boats and worked with OTTO FUEL on the 48's and ADCAPS. Very nasty stuff, if I remember correctly, it produces it's own o2 supply as it burns, and is very caustic. also too hard to find outside on the USN.

Cheers.

Mike