I would also add to your requirements that it can do at least 4-6 such trips on a single charge. If you want to use the DPV on a weekend or several days of diving without the hassle of opening/closing them for charging between dives: this would take too much and become an annoyance, the difference between a single use toy and a serious diving DPV. A pool toy also may not be able to tow you and buddy a distance of 600 meters if his DPV dies, for example. You need extra juice.I want a scooter that works with one hand; that can pull myself around a wreck and between wrecks. I need one that's reliable to get from one end of a battleship (e.g. HMS Audacious) to the other and back again (about 600m with deviations) within the bottom time limit.
Add external charging without opening to requirements too.