I was helping Di in her cabin, using our central vacuum system, or more accurately our engine room mounted shop vacuum with 40 feet of hose, when all the smoke alarms on the boat started screaming "Alert: Smoke detected in the basement".
Our 6 fire and carbon monoxide alarms are all linked via their own proprietary WiFi network, so that when one rings, they all do. At well over 100 decibels each, it makes for a very loud alert throughout the boat, leaving little risk that an alarm in the lazarette won't be heard because we're at the other end of the boat.
Our friend Sean who kindly kept an eye on the boat during my recovery decided to test the system on day and had the shock of his life when all 6 units responded once he pressed the test button on one of them. They are loud, and will wake anyone on board, wherever they may be.
Being a shore based system, the grating electronic voice only has pre-set locations for houses. Garage, Main room, Office, Guest Room, and so on. So I had to assign logical names that I would remember in an alert for the various units' locations.
Salon is self evident. Office is the pilothouse (where the navigation work happens). Shed is the lazarette, since you have to step outside and into the cockpit to access it.
Basement is the engine room, since it sits below the salon and galley.
So I rushed to the engine room, silenced the alert using the detector in my cabin, and sure enough found the vacuum cleaner was on its last legs, smoke pouring out of the electric motor. The smoke detectors had done their job and alerted as soon as the problem started, so the vacuum cleaner hadn't caught fire yet. That meant I wouldn't need the strategically located fire extinguisher at the engine room's entrance, and all I had to do was to unplug the vacuum cleaner to stop the nascent electrical fire.
Confirming it wasn't going to burst in flames, I then started the engine room evacuation fan to clear the acrid smoke away. We later opened all the boat's doors to clear the inside air as well.
We normally test our smoke alarms every other week on a Sunday, so this alarm happening on a Saturday evening counted as our official test. it was entered as such in our computer based maintenance program.