OpenMarine

Full Version: MOB Feature
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Hello,

It will be good if we have a feature on pypilot to stop the boat, like in nke pilot.
I think a signal-k sentence to stop the boat can make this:
 - if there is a windvane, the boat face the wind
 - if there is no windvane, the boat go to heave to

Il would allow to use some cheap bluetooth tracker, and, with a separate process, when the link is lost, the process stop the boat. In solo sailing, this will potentially allow a man overboard to come back in the boat.
An excellent suggestion. A spare GPIO on the Pi could be used to trigger the MOB function, then you could easily connect up an external MOB button (for when sailing with a novice crew) or a simple bluetooth lost signal detector for when sailing solo.
I thought about this years ago, but I was also afraid to actually test it. As you say it will "potentially allow a man overboard to come back in the boat" but there is no guarantee. I'm also afraid it gives a false sense of security.

For bluetooth, or even RF, it just needs a device which pings the AP every second. If the button is pressed it could send a different signal and also a timeout. The wind mode could steer into wind, but it really depends on the boat what the best action to take is. For compass/gps course the autopilot doesn't know which way the wind is, it could maybe guess based on heel, but again it really depends on the boat. Some boats if you try to do this, depending on the traveler or if there is a preventer, the boat will actually start sailing backwards and you may not catch the boat, or further action by the autopilot may be desired to keep the boat in place. Other boats may heave to at a faster speed than you can swim depending on the situation.

So this is not really better than dragging a line behind the boat that if you pull hard enough it breaks a small fishing line and releases the autopilot as well as pulls the rudder hard over, but also with this you have a line to pull yourself to the boat at the cost of the line dragging.

So a better option would be a waterproof remote so that you can still steer the boat back to you. This is more difficult with the sails up if the boat is not self tacking.

If there are other crew, this safety button is more likely to succeed because it would stop the boat right away and possibly wake them but also sound an alarm, and then you would not be far from the boat after falling making the chances of retrieval easier, but I think the locator beacon that transmits gps is still needed for really bad cases.


Or you could do like me and remove all your life lines, never wear a harness and sail without any protection besides the strength of your grip, but I'm now pondering the harness option again. I had several dreams about falling overboard only to wake up on the boat in the middle of the sea.
(2020-12-19, 07:20 PM)seandepagnier Wrote: [ -> ]Or you could do like me and remove all your life lines, never wear a harness and sail without any protection besides the strength of your grip, but I'm now pondering the harness option again.  I had several dreams about falling overboard only to wake up on the boat in the middle of the sea.

Big Grin I also thought I was Superman in my youth... oh... at least into my early 40's.   Tongue

Now... I'm thinking the same thing about a widget.  ESP8266 using UDP, small LiPo.  Using MPU Sleep, could easily have at least week-long battery life.  Could make WiFi output power configurable to tune to size of boat, and limit desired range (and increase battery life).  Seal it up in plastic, use wireless charging.  Light, tiny... I can see it.

But...  I think I'd still implement a harness AND the line out the back, fishing line and pulling a switch (KISS principle).  Thanks for suggesting this method.  Wink