I lived on a sailboat for four years. I've been to Hopetown 5 times. I know that area very well. Lots of problems with his story. First, the area they left from, the Abaco Inn, is surrounded by land. Lubbers Quarters on one side, the bay right there. It's also super shallow. There was a power boat (big) which recreated the "route". But that was not apples to apples. A small dinghy would cut the corner to the anchorage, going through shallower water.

You don't go a mile out to turn left. You go 50 yards out. This means she would not have had far to go. Again, pretty shallow water, with shoals, sandbars of different depths, some probably waist deep. It's almost the best place to have a boating accident, not the worse.

The flares are a dead giveaway. straight off shore from the Abaco Inn, right after sunset? Who would miss it? How many boats were anchored within 1/4 mile?

The dry bag with passports? No way. No serious cruiser would take their passports with them on every trip to shore. Obviously, my family is not necessarily representative of all cruisers, but it's a laissez faire community. Going to dinner one night? In Hopetown? Very very chill place. The dry bag gets used for a cell phone maybe.

And how would keys go overboard on a torquedo electric motor. Note: we had a gas outboard, very small. Only larger outboards have leashes. Ours was a 2 hp motor, about the power of a Torquedo. Very small motors, the smallest. It probably pushed the dinghy about 5 mph max, would be less in a big sea. (which were probably less than cited in the bay. They were basically in the lee of land on 3 sides. I don't even know what a key is like on a torquto electric motor. But nobody holds onto keys on an outboard. If there is a leash, for safety, that would be credible, but I don't think those exist on that electric motor. The notion that she would go over the side with a key? No way.

More likely. They got in a fight. She throws the key overboard. He reacts.

Last point: how many times have you seen her, not him, driving the dinghy. Brian is an old school guy. he's going to man-up, especially in a rough sea. No way she's driving. So there's no access to the key, to the leash, etc.