I have done a couple "Hot drops" but that is with the boat moving away from you as you exit. Can anyone tell me if they have ever done an entry with the prop running but the boat not moving away from the entry point? Not sure I can imagine a situation like that.
I would speculate that it would take a lot of water activity to push a diver into a Prop of a boat that is moving away.
Are we sure if this happened on entry?
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If you are drift diving, and the intended dive is on a wreck or a SPECIFIC place on a reef.....the captain is essentially running the boat along a path ( which is from gps, or visual marks), and as he approaches where he thinks the desired structure will be, he begins to look ALSO at the fathometer....often when the captain suddenly sees the fathometer show a huge spike, signifying that he has just arrived at the dive site in this "path", the captain will then try to "FIX" the issue that he has just driven the boat over and beyond the ideal point -- Let's say the inertia carried the boat 20 feet too far --so he reverses the engines, going from 5 mph forward, to 5 mph backward....and he does this for about 2 seconds.....
Normally at this point, you would expect the captain to shut down the engine....However, there are captains that instead, will throttle down to minimum, and then shift to neutral....and then say "DIVE, DIVE, DIVE"....
The problem is, when he throttles down to minimum, he might "think" he then succeeds in getting the engine in neutral, but he does NOT actually know for sure if the prop has stopped spinning. It is even possible for the shifter to be in the neutral position, but for the prop to continue to be engaged. Boats are NOT like your car in this.
If this did happen , and the divers jumped in, the boat could be slowly backing up...with the divers thinking they are about 3 feet to 5 feet behind it, as they begin to dump BC, perform final checks, and start to descend---in the next 4 seconds, the divers go from being plenty far away from the boat, to having the boat catch them as it backs up, and begin to run over them.
This is why you don't let a captain drop you with his engines still on. But even most divers that have done thousands of hot drops, will not be thinking of this....we tend to do what the captain tells us, and DIVE means dive....It is a MAJOR issue in drift diving, one that has gotten very little attention from anyone. In this scenario, the real fault is with the captain and boat. The diver is not supposed to be forced to second guess the captain's commands. Because WE may decide that this is an industry wide mistake, ignored by the industry, we might suggest that all of us think about CHANGING the way we react to Captain commands, like the Dive command.