Fire - Shut off solenoid

I would think for safety reasons, an auto shut down of main engines is not advisable, restricts emergency maneuvers etc.

Virtually all of the engine room mounted fire supression systems automatically shutdown the engines and generator(s). So they don't ingest the halon or whichever gas and destroy themselves and to assist with fire suppression. A good fire system will also have dampers that close the boats air vents for the engine room.

As for where to get the piston, look to the manufacturer of the fire system you have on-board. The piston looks to be air powered by whatever is in your fire supression bottle. That is neither a Detroit Diesel or Hatteras Yachts part.

I had a good friend who is very experienced damage his boat after drifting into a bridge after his engines shut down.

he repeatedly try to restart, buzzers were going off, and his anchor failed and the boat became lodged under the brigde.

after things settled down he realized that his fire suppression system had shut down the mains, apparently a wire had become loose causing the system to shut down.

No fire.

The system is desinged to shut down the engiens in the event of a fire so the engines do not suck the halon out of the machinery space. The halon is what smuthers the fire.

Mine and my buddies have an emergency restart/bypass, but he nevere expected or planned for the system to trip without a fire.

The Halon bypass is now in the back of my head and part of my emergency restart check list.

As your 80 ft yacht approaches the dock at a sedate 4-5 kts, there are 30 guests waiting to board and watching intently as you approach, some paddlers are also interested in the general area in their canoes the auto fire system kills the mains and how many do you kill or injure ?

Before spending a lot of time and money to replace the cylinder, how about just put some air to it and see if it works. If it does then all you need is a shoulder bolt.

And as far as the "automatic shutdown" is concerned, make sure that it is indeed automatic and not part of the manual discharge procedure. You may have an alarm, then if and when you decide to discharge the system, engine shutdown is part of that process.

Read the book. If you can't find a book, contact the fire system manufacturer and have them inspect the system and tell you how it works ... they will also provide you with a manual.

there is a green light on the dash when the system is armed.

a red light and alarm when it is discharged, the discharge activates the engine shut down.

There is an emergency restart or bypass button at the alarm.

I agree with Pascal, you have to know the system you are operating and emergency proceedures. like a pilot, have a check list, and practice for emergencies.

Heat, oxygen, fuel = fire

Fire in engine room = bad

Fire in eigine room that re-ignites after engines suck halon out of ER = very very very bad