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Comment by StianOvrevage | Hacker News Reader

I installed the Fell Marine Mob+ myself on my 23 foot day cruiser a year ago and it works very well.

The only problem I've had is false positive cut-offs when I'm on the dock untying or when I prepare to dock and I use the arm with the wireless FOB on in the rear compartments of the boat.

I could probably fix it by angling the antennae so that it was upright instead of pointing out horizontally behind the base unit, but TBH it's such a infrequent issue and only happens at no/low speed anyway that I haven't bothered.

On the plus side at least I know that it does cut the engine and probably would in a real situation as well.

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Go out with a buddy sometime on a day with a light wind. Put your boat at a slow cruise and then jump off (carefully). See if you can actually get back to your boat before you’re exhausted (and need your buddy to pull around and pick you up).

In a light wind or current an average boat is still going to be moving faster than most people can swim.

The wireless kill switch is good. But pair it with an inflatable PFD.

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.

There are folding fins now available for travelling scuba divers. However, they are still rather bulky and not practical for boaters to carry on a PFD. If the boat is moving faster than a couple knots you won't catch it even with fins.

https://www.kickstarter.com/projects/exotech/folding-fins-a-...

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.

> One hand for you, one for the task.

Similar to '3 points of contact', which is my personal mantra. Reminds me to keep feet planted.

Many of the boaters who fall off have a high blood alcohol content.

Thankfully the USCG PFDs and tethers still work in the presence of ethanol.

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.

As part of the Royal Yacht Association “man overboard” training the instructor would throw a polystyrene head in the water and yell “man overboard”. We were taught that everyone not at the controls would point at the head until it was recovered. Helped enormously to have people extend their arms and keep their eyes on it. A head in open water is tiny. I thoroughly recommend RYA training.

At the sea scouts, we used a fender with a weight on one end. It would be unexpectedly be thrown overboard, and everybody was supposed to react immediately: yell "man overboard", have someone point, shout "swim!" at the man overboard (because sometimes they forget), and sail a certain pattern in order to arrive at the man overboard at a controlled course. We practices that dozens if not hundreds of times.

We did exactly that - well, one of the crew's job was to fix eyes on the head (not much point extending the arm, we turned the sailboat as quickly as we could), but due to being just a typical sail yacht's one meter above sea level it took only a few seconds of movement of the boat for the head to be invisible among the choppy waters.

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.)

False negatives are more worrying. On a small speedboat, a common cause of death is that the captain falls overboard while the boat is doing a sharp turn at speed. The boat then does a 360 circle and within 10 seconds runs over the captain before anyone else in the boat can intervene.

Will these wireless keyfobs reliably cut out within 10 seconds when the boat never goes more than say 60 feet from the captain? I suspect not.

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.

The accident described above is basically the same as happened in my hometown in October 2021. There was no one else in the boat but many witnesses on the shore. The whole community greatly affected.

https://www.couriermail.com.au/news/queensland/rockhampton/a...

Here is a news report with video footage of one such incident (the part where the victim is decapitated is clipped from the report): https://youtu.be/3IwhsYfnNvs

I am personally aware of quite a few speedboat related accidents, some fatal, and this is a common pattern.

The types of death that people imagine (boat sinks, boat engine dies and drifts out to sea) tend not to be killer in small boats because they mostly operate in busy waterways near shore where someone else will come help.

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.

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