It's a tough engineering challenge but it be cool if there was some kind of collapsible 'foot flippers' (is there a more technical term?) one could pull out of like a tube attached to a PFD.

I was watching the video of that boat that rolled at the Columbia river outlet in Oregon and the USCG rescue swimmer was astoundingly fast with the fins on.

That's a very good suggestion actually. It's probably a very helpful, and I expect humbling, exercise.

(Have to remember to teach the buddy how to override the MOB-system so that he can actually start the engine after I go in the water though, lest it become a real situation)

I use a fanny-pack style autoinflating PFD which actually comes with a ring to connect the lanyard to. Definitely agreed you need both.

Absolutely concur. Michael Phelps swam an average 3.8 knots when he broke the 200M Freestyle world record. That's also with 4 pushes off a wall. You simply cannot keep up when your boat is going more than a knot unless you're an excellent swimmer who also happened to already be naked and barefoot when they fell in.

The key is to not fall off in the first place. One hand for you, one for the task. Also, if you're solo offshore you really should be wearing an auto-inflating PFD with tether and a PLB. Everybody has their own risk tolerances but if you don't wear one most of the time at least clip in when you take your pants down.

I and friends owned a 40-foot sail yacht when we were younger. We did some experiments with people, dummies, and various items which had the same profile above water as a human (i.e. head-sized). We would drop (if it was cold) a dummy or a ball or something in the water, and then cry "man overboard!". The crew immediately dropped the sails, we didn't even consider lowering them - took too long. And turned on the engine and started searching. But even those few seconds were enough to lose sight of the dummy/person/soccer ball if the water was just a little bit choppy (typical nice sailing weather), because a sail yacht sits quite low in the water. We could hoist people up in the mast, but setting that up took too much time.

So, we introduced rules.

1) Nobody on the deck without clipping a safeguard line to their belt. Ever. We stretched a wire all the way both sides of the yacht, and everybody just clipped a lanyard to the wire. We could move relatively freely with that.

2) We put a flag on a fishing rod at the thin end and a floating element a foot from the thick end, and a weight at the thick end. If someone fell overboard, another crew member would immediately throw the thing in the water (we had it set up at the rear of the yacht), because that pole in the water is so much easier to see than a person, also from a long distance. NB: We didn't have anything like that Garmin tracker mentioned in the article - those things weren't available back then - but this actually worked pretty well when we tested it.

3) After all the testing we actually concluded that if someone fell overboard in choppy waters and if nobody saw and could throw the "flag pole" in the water we could as well just continue sailing. We never managed to find the soccer balls etc. we dropped in the water, whatever search pattern we used (those you find in books about rescue). Thus we established hard rule 1)

4) Zero alcohol unless we were moored for the night somewhere. This was a 100% enforced rule. It's incredible how little alcohol you need to decide to not bother with the lanyard when you just need a moment out there.

I've briefly swum behind a boat that was anchored, but in a steady current (between some Danish islands). It's really like the boat is speeding away from you, even while anchored. (We had some safety measures which I mostly forgot, but it included a very long line behind the boat. Not sure if we were attached to that line.)

Would a wired one that went unused prevent that? That would seem to be the core problem in your scenario - the existing technology that would not have a false negative here is going unused.

Also, can you cite any sources for that event being common (relatively at least)? Not that I doubt you specifically, the scenario is just so horrifying that I am generally having trouble accepting it.

Is there a reason people can't just have seatbelts of some type for that?

By the inverse square law accuracy should be better at close range, cutting out at 10 to 30 feet but not 0 to 6 feet should be possible, especially with UWB, and even moreso if the fob detects water directly.

Radio waves propagate very poorly in water compared to air, so there's a good chance that the signal is lost as soon as the wearer falls in. From there it's just a matter of how long the timeout is, and the latency of cutting the engine.

I assume this. https://www.amazon.com/product-reviews/B075MMHYMK/

Overall the rating is pretty good but definitely a number of one stars.

The challenge with a lot of safety and backup systems is that you might never need them, but if you do need them they absolutely have to work.

https://www.amazon.ca/product-reviews/B075MMHYMK/ref=acr_dp_... top result in Canada

This got me thinking about survivorship bias in ratings for life-saving devices. If the device fails to save your life, you're not going to be able to give it a poor rating.

What difference does it make? Is an iPhone from Amazon worse than one from the Apple Store?