Hi I am kicking around the idea of getting a DPV or two. I would like to know:
1. how you currently employ it.
DPV's are used to extend your range, decrease your swimming workload and/or deal with currents. The extended range is an obvious benefit for exploring places you normally would not be able to (or want to) swim to, but decreasing your swimming workload means that your muscles are not using oxygen as fast, so your breathing rate can be slower and your gas will last longer resulting in longer bottom times. For dive sites subject to strong currents, it can mean getting out of the water where you got in or being able to get back to the boat, but you should always have a contingency plan in case the scooter dies. Also, the nitrogen buildup does not change, so with a longer dive you still need to factor deco in at the standard rates.
2. how difficult it is to maintain it.
Other than rinsing it off after saltwater dives, most DPVs recommend that you change the shaft seal annually (unless the DPV does not have a shaft seal, of course) along with the body o-rings. Some brands recommend sending the scooter in for this service. Other than that, basic o-ring cleaning/greasing and recharging are all that is needed. Most scooter, you will need to open the scooter to recharge the batteries, which increases the chances of getting dirt/sand on the seals or damaging the seals during reassembly. That, plus convenience, is why we use an external recharge connector.
3. most common problem areas.
Leaks are an obvious problem. Poor attention to o-ring cleanliness and condition can result in leaks at the body/tail connection. DPVs with shaft seals that are poorly maintained is another possible leak source. Additionally, dropping the scooter or ingesting objects that result in a bent propeller shaft can lead to almost immediate shaft seal failure. Other than that, switch failure (either failed "on" or failed "off") is a possibility, but rare.
Cheers,
Jon