DPV/Sea Scooter problems anyone?

[rjack321]

That's one of the ideas I had in mind as well! But I think the lecturers will think its a bit too simple for this project

I think you are underestimating the challenges of building a "good" scooter...

ThaWhat do you guys think of a DPV that uses waterjet propulsion as opposed to trolling motors?

Jets are only about ~70% efficient compared to a comparable propellor. Are you prepared to make this thing oversized to achieve the same speeds? Or given a comparably sized motor (say 600W) live with the reduced speed?

I'm not sure what problem a jet solves relative to the normal propellor/shroud/nozzle. You might instead of the jet consider making a turnable Kort nozzle. That would be complex, not done before, but not be an obvious power loser.

 

[ben.mcgeever]

Batteries, batteries, and more battery work.

For all manufactures, batteries are always an issue. They are expensive, made in low volume, and don't last forever.

Come up with a way to get a zinc air fuel cell in a scooter.

 

[boulderjohn]

How about a dependable external battery reading, the equivalent of an SPG, so you know when you are unexpectedly running low on juice before your scooter quits a few thousand feet back in a cave?

I just heard a story about a multi-scooter dive that went bad when scooters did exactly that. Both divers had their scooters die at approximately the same point. There had been a power failure during the night when their scooters were charging, and they did not know that in that case, they had to disconnect and reconnect the charger--it read a full charge in the morning when it was actually on partially charged. Both divers were able to swim to their next stage bottles, but only barely.

 

[kelemvor]

H2O2 propelled jet scooter?

 

[Matthew Yung]

You might instead of the jet consider making a turnable Kort nozzle. That would be complex, not done before, but not be an obvious power loser.

Hmm..I had a chat with my supervisor about this, who also dives, and what he believes that it could be obstructive if compared to a water jet propulsion. However, I did a bit of research into the Kort nozzle, and your right, I did underestimate how challenging this could be =P. So I'll definitely be keeping this option open, if not incorporating so of its characteristics into the design

I just heard a story about a multi-scooter dive that went bad when scooters did exactly that. Both divers had their scooters die at approximately the same point. There had been a power failure during the night when their scooters were charging, and they did not know that in that case, they had to disconnect and reconnect the charger--it read a full charge in the morning when it was actually on partially charged. Both divers were able to swim to their next stage bottles, but only barely.

After I read this, I know I'm definitely going to incorporate a battery indication feature haha!

 

[rjack321]

After I read this, I know I'm definitely going to incorporate a battery indication feature haha!

The Makos have a simple green/yellow/red indicator. Its "ok" mostly because these scooters use SLA batteries which have a fairly linear discharge curve. What type of battery (or fuel cell lol) are you planning on using? If you check out the 2011 Tahoe benchmark you'll see examples of non-linear battery dischange curves which should be quite a challenge to work around.

 

[Mr.X]

The Makos have a simple green/yellow/red indicator. Its "ok" mostly because these scooters use SLA batteries which have a fairly linear discharge curve. What type of battery (or fuel cell lol) are you planning on using? If you check out the 2011 Tahoe benchmark you'll see examples of non-linear battery dischange curves which should be quite a challenge to work around.

That indicator on the Mako is so unreliable. But, entertaining. With the SLA - have to burn test the batteries to get any reliable estimate of time. It would be cool to get some kind of digital readout of batt. life without punching a hole through the hull?

 

[rjack321]

That indicator on the Mako is so unreliable. But, entertaining. With the SLA - have to burn test the batteries to get any reliable estimate of time. It would be cool to get some kind of digital readout of batt. life without punching a hole through the hull?

A waterproof Watt's Up.

 

[Jon Nellis]

A waterproof Watt's Up.

That could be done on your Genesis, using the recharge connector, but would require opening the scooter to recharge it. The other option is to use the test port for the wire feed through. Wireless does not transmit through aluminum all that well.

 

[Matthew Yung]

Time to resurrect this thread I think. It's been 7 months since I've posted and I've finally designed and built a prototype DPV using waterjet propulsion. Took me a while and some, well acutally, a lot of advice from my supervisor to build this beast. However, although I'm getting the results I want using Flow Simulation from SolidWorks, I struggling to find a practical way of calculating the thrust of the unit. Does anyone have any ideas of getting about this?