I did the math on these and decided that they were not of much use, certainly not as useful as wearing a PFD with a signal device. The gizmo takes some seconds to shut down the engine assuming a good radio transmission. If a small boat on plane, it might be a quarter mile away by the time it stops coasting. Even the old school kill switch tether that stops an OB engine immediately can make for a very long swim if on plane. A large trawler would coast farther, and with the increased windage, it might also be a quarter mile away. Kind of like boating and wearing a parachute for safety. If it makes you feel safer, that could be dangerous.
It's about more than just the helmsman or passenger getting back to his boat....
One of the recent videos I watched on youtube was a Coast Guard profile show...some channel called DangerTV
one of the calls they highlighted was a runaway boat.... a twenty something foot center console on plane, wide open throttle, at night, no lights on... they guy fell off. They had to clear the area (boats on anchor, etc.) for hours and let it run out of gas....in a busy harbor, Miami area I think it was....
and then another episode showing a guy that was cut by a prop. The Boatswains Mate said that he'd been on two other prop strikes previously and neither of them made it.
I think the idea of it seems wonderful. I'm guilty of not wearing the clip on lanyard on a small boat but I'm reconsidering that... on a big boat though, I can still imagine there's some risk...but having a string lanyard makes less sense.
Like others though, I'm doubtful....reliability of wireless things, keeping up with fresh batteries, actually wearing the thing,....all sorts of loophole problems...
Just brainstorming....I'm reminded years ago of operators in papermill control rooms were often set up with a button they had to press periodically. I don't recall if they were set up to actually initiate a shutdown or what.... Seems like I remember a periodic buzzer and they'd press a button to reset it. I recall one guy that would lay back in his chair with a cut off broom stick in hand....looked like he was sleeping. The buzzer would barely sound and he reach up to the button high up on the overhead panel with the stick...without ever opening his eyes.
Some kind of a Deadman switch system like that might be of some help too... my car even has it...a capacitance system that knows when I let go of the wheel.