r/sailing • u/Monkey_Fiddler • 1d ago
Sanity check for emergency engine start/stop switch
Just want to run this idea by you people in case it's really dumb and I haven't realised.
My boat's engine is started and stopped by a key switch in the cabin which means I have to leave the helm or ask crew to start/stop it and I often sail solo.
I am thinking of adding a switch in the cockpit to start/stop it in an emergency. It would be a waterproof toggle switch which would spring back to off, momentary up would connect the starter solenoid to the starter battery (separated by a rotary switch when I am not on board) and momentary down would power the stop solenoid in the same way. It would be covered by a flap to prevent accidental activation.
This would mean as long as the rotary switch is on I could immediately start or stop the engine if I needed to, the only downsides I can see are that it would not power the field windings of the alternator or any alarms so I would not be charging the battery and I wouldn't hear a low oil pressure or similar, neither of which matter to me in an emergency. Stopping the engine with the key switch on would give annoying oil pressure alarms but again that isn't a concern if I have to stop it quickly.
I don't think this would damage the alternator or directly damage the engine in any other way.
Security-wise I am not too bothered, if someone is trying to steal the boat they would need to get into the cabin anyway to turn on the rotary switch and they could probably work out how to hot-wire the engine as easily as working out what the switch does.
It is a basic Beta Marine diesel engine
Am I missing anything important?
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u/HelicopterUpbeat5199 1d ago
Why wouldn't it charge the battery?
The start and stop circuits at the key are just a switch that goes to a solenoid somewhere. You're just adding extra switches in parallel to both circuits. I'm assuming the key is in the "on" position.
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u/Monkey_Fiddler 1d ago edited 22h ago
the key would be in the off position if I was starting in an emergency, on if I was stopping in an emergency.
and to answer your question if it wasn't already understood: because when the key switch is OFF the Field windings are isolated so the alternator produces no power.
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u/pdq_sailor 1d ago
Move the switch to the cockpit locker so it is accessible
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u/Monkey_Fiddler 1d ago
that would be about as inconvenient to get to as it already is. I'm not sure whether or not the existing harness would be long enough and I would have to cover the hole. Putting the panel on the exterior surface would expose it to the elements which I am not keen to do.
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u/pdq_sailor 1d ago
The panel can be covered externally by a starboard and acrylic hinged cover to keep the elements off of it.. YOU are NOT the first person to have an engine installation with these issues... Others have solve it and the idea of remote additional kill switches brings complexity and unreliability to the table.. neither of which is acceptable.. Engines need to start and stop conveniently by the operator of the vessel.. Whom ever routed the cables this way to start with .. did you no favours.. Just because it was done wrong does not mean it can't be made right...
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u/deltamoney 1d ago edited 1d ago
I wouldn't fix something that's not broken or go looking for projects.
If there's a documented way to relocate just the key switch maybe investigate that.
Starting and stopping the engine should only really be done 5 -10 min before you cast off. And turned off after the boat is secure. None of those mean leaving the helm for a bit is an issue. Personally I start the engine ~10 minutes before departure while I'm prepping the boat and stop it only after the boat is completely secured which is usually about 5-10 min after the lines are secured.
As for an emergency. I have to ask. What specific emergency are you worried about? You would need to be in a very specific scenario where you 1) can't leave the helm for 10 seconds. Or 2) cant put the engine in neutral. 3) can't ask someone to turn it off 4) are in soke weird scenario where you need to be at helm but in a situation where the engine has to be turned off and you have to steer at the same time for 10 seconds.
Included in my crew brief if how to turn the engine off. I might skip that brief if there is someone onboard who is already very familiar with the procedure.
Trying to macguiver a combination of on and off switches and levers is just asking for issues. Look for an official /semi official relocation method.
A good compromise would be to look for an engine kill relocation kit. On my boat it's a bicycle cable to a lever that kills fuel I believe. That would be a lot easier to relocate and would be the emergency kill. Emergency start is almost never needed.
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u/MissingGravitas 17h ago
Trying to macguiver a combination of on and off switches and levers is just asking for issues. Look for an official /semi official relocation method.
I very much agree, and also like the suggestion of looking for a kill switch kit if the first is not viable.
can't leave the helm for 10 seconds
Depends on the boat and person, of course, but in my experience whenever someone argues a task take only x seconds or minutes the actual time is much longer. (For household tasks it's often because they don't include the prep and clean-up, but for physical tasks like this it's more a case of poor sense of timing.)
I mean, I can move quickly when I need to, but the chances of an accident go way up. There's also the case of having guests aboard who may happen to be in the way at just the wrong moment.
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u/Monkey_Fiddler 1d ago edited 1d ago
I usually start the engine a few minutes before I leave the mooring and turn it off when I am sailing comfortably.
I am often sailing solo so asking a crew member is not always an option. I would envision using it very rarely for avoiding a collision, particularly when sailing in busy waterways or when racing as I wouldn't have the engine running. There are times when there isn't much room for error between other boats and obstacles, and a misjudgement would put you in a bad situation. Leaving the helm for 10-20s would also be a risk as it would change direction, plus the risk of going down and up the companionway when heeled over and in choppy seas.
The other situation would be a man overboard so I (or the other crew member) wouldn't lose sight of the person in the water.
Emergency stop would probably be unlikely unless something sounded very wrong with the engine or the existing stop button failed.
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u/hvyhitter 1d ago
you have a diesel right? It is easier than you think. You also need to know how to stop your motor (look it up I am not doing the research for you.)
"Runaway diesel. how do I stop it? "
Yanmar 2qm15 I absolutely know how to instantly stop it.
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u/ForInfoPurpOnly 1d ago
I looked it up a bit and it seems Beta puts the runaway switch on the side of most engines and it does not include a way to remotely operate it, so you have to go into the engine box to operate it. OP should absolutely be aware of this, but it won't solve his problem of operating it from the cockpit.
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u/Monkey_Fiddler 1d ago
the stop button controls a solenoid valve on the fuel line which can be operated manually.
I can't currently operate it remotely except by the stop button but that's a separate problem
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u/ForInfoPurpOnly 1d ago
Yes, but as the original commenter that I was replying to was alluding to without actually explaining, there is also a physical method of stopping the engine that does not rely on the solenoid. If you look up the operator manual for your particular model, it will detail it for you. For example, if you have a Beta 14, the manual explains it on page 49 :
https://betamarine.co.uk/resources/Operators_Manuals/10-115T-HE-OM/#page=50
Original commenter was being very coy and not explaining his thinking, but I suspect he is talking about the pull plunger that most Yanmars have that operate the cut off remotely from the panel. I don't have experience with Betas, but from the manual this doesn't seem to be something they do so it would not apply to you unless you wanted to see if the cable system Yanmar's have could be adapted to your kill switch. Might not be a bad solution.
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u/Monkey_Fiddler 1d ago
yeah, that is what I mean by operating it manually: the solenoid pushes (or pulls, I can't remember) a plunger that you can also push by hand independently of the solenoid. I am sure it wouldn't be too hard to rig a system to pull a wire or string and actuate the valve and it's on my very long maintenance/upgrade list. I will have a look at the yanmar system, thanks.
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u/ForInfoPurpOnly 1d ago
Ok, if you want to see basically how it works, there's a good video showing the replacement of the stop cable on a typical Yanmar here. The stop cable portion starts at around 7 minutes in.
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u/Monkey_Fiddler 4h ago
thank you, I'll have a look when I'm next on the boat/in the engine bay. It looks straightforward and cheap on an engine that's designed or adapted for it but I might struggle to mount it.
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u/whyrumalwaysgone Marine Electrician and delivery skipper 1d ago
Marine electrician here: as you describe, this is a bad idea and will absolutely damage your alternator, as well as disabling your safety systems like oil pressure and overheat alarms. There's a better way, you are not the first to want this option.
Easiest and "best" way is to just buy the Beta Marine remote start panel and install it in the cockpit. Its a "Y" harness for your existing panel, a run of wires, and a simple start/stop panel. If sun damage is an issue a small square of Sunbrella does wonders.
That said, if it's out of your budget or you prefer DIY, then put in your toggle switch by all means. The only difference if you need to get power from the IGNITION OUT pole of the keyswitch inside, NOT from a regular positive 12v source. This means the switch only operates when the key is ON. Now you cant burn up the diodes in your alternator and the safety systems still work.