DIY DPV - scooter

[lucca brassi]

I have a question for DIY DPV builders :

It is possible to modify a some electromotor for lake fishing boat ( like RHINO ,MINN KOTA..etc ) I have in my mind to cut off rudder pillar and to put all controls an battery pack into the tank in front of the scooter . Depends on electromotor can push between 500-1750 kg boat - think that this is way to much , but boat more glides on the water than push it through like diver do -to much water resistance. Look at:

RHINO PARTS

So I think:

- I have simple solution for battery tank
- I got original control with speed steps, which I can simply modify by using reed
switches for trust controll
-I got all ready water sealed electomotor ( for cheap electromotors with brushes ,
more expensive brushless) PRESSURE TO DIE UNKNOWN
-I got standard cheap parts ( clutch , propellers with2-3 blades)

So I can also purchased some SEA-DOO parts like thrust tube.

Now if I put all together

1. Battery tank fom POM or PVC with electronic ant battery pack it is sealed on the
front and the end with conic lid

2. I mount part with sealed electromotor and SEA-DOO thrust tube in some kind
of cradele from aluminium (only front of the electromotor - designed like drop-
hydrodynamic - so electromotor can cool itself ) only wire for power leads direct
to the battery tank

3. In to the battery tank leads control wire from handle with reed switches for
thrust control

I hope that you can imagine what I want to tell you! Can this work or it is mission busted

Best regards

 

[DA Aquamaster]

Before you re-invent the wheel - check out this site:

scuba tow

If you read the details they use a 24 lb thrust motor on the two motor model and a 40 lb thrust motor on the single motor torpedo model. In my opinion, their performance stats are wildly optimistic as 4 mph is 350 ft per minute and a top end commercial scooter will do 200-225 fpm and that is generally with motors in the 60-70 pound thrust range. I also doubt the burn time on the two motor model would be all that great on a single motorcycle battery. They are claiming 1.25 hrs with intermittent use, and I think "intermittent" would be the key term there.

They might get that performance with a swimmer rather than a diver in doubles, but it is still awful fast on only 40 pounds of thrust.

In any event the torpedo design has some potential and the plans are fairly cheap and may provide some useful ideas.

On the Rhino site, the number after the "VX" in the model number is the thrust in pounds and I'd go with 54 pounds, just because it would get you in the same general ballpark as a decent commerical scooter as opposed to the much smaller sea-doo scooters.

If it were me, I'd go large on the motor and then scale the battery requirement to get a 60 minute burn time, then design the hull to contain the battery, switches, etc and make it close to neutrally buoyant.

 

[fdog]

Don't expect to save money! Odds are you'll end up with a reliable, serviceable scooter cheaper and easier just by buying one.

Doing something like this is more for the joy of the journey, and given that, I think it will do fine. Have fun!

Here's a web site you may wish to peruse, too: Tahoe Benchmark


All the best, James

 

[fdog]

Also, results from the 2009 tests show that 40 lbs of thrust will produce 200 fpm. 54 lbs would produce 232 fpm.

This assumes thrust values are true as stated by the motor/prop manufacturer. We have found that most manufacturer thrust values, as well as speed values, are wildly inflated.


All the best, James

 

[lucca brassi]

Don't expect to save money!

Completly agree with you. My nearest scooter suplier is arround 200km away from me . Just an idea ...

SUEX

 

[mikerault]

Here is what I have been messing around with. I have to put on the final latches and test it.

http://www.scubamage.com/files/ADS_DPS_Parts.pdf

Mike

 

[lucca brassi]

Nice ....but

Motor, gearhead (170 watt minimum)

I think that this it is not right way.....

Motor should be brushless (PWM controlled;power torque), without gearbox (weight , losses). Motor like is built in car steering wheel - hydraulics servo (350W ,brushless ) with controller. But this is other story...

The main idea was to modify complete electromotor for lake fishing boat ( like RHINO ,MINN KOTA..etc ), to minimize costs , because all needed parts are practicaly in one piece (with except of thrust tube and battery tank)

 

[DA Aquamaster]

This assumes thrust values are true as stated by the motor/prop manufacturer. We have found that most manufacturer thrust values, as well as speed values, are wildly inflated.

Absolutely - get the big motor and hope for the best.

 

[mikerault]

I was salvaging from an existing system, yes, a bigger motor is better. The problem with many of the trolling motors is that they are only good (seal wise) to about 15 feet of depth. You need to be careful about the heat dissapation from the motor, it can cause an overpressure and unseat the housing and cause a leak.

 

[kavka]

If you will use complete housing you will probably have some problems with leaks and its also to weak for deeper dives. 10m maybe, but I dont think any deeper.
Regards Gorazd