KISS Companionway Alarm
When checking our blog’s statistics the other day, I came across a website that had linked to a couple of my security-related posts (specifically this one and this one). While looking through their site, I noted that they also had a post discussing alarm systems for boats. You may recall that, once or twice in the past, I have alluded to our super-secret boat alarm system. Up to this point though, I have yet to post any details on it. Working under the assumption that no would-be thieves will be following our blog, I decided to share the details on our KISS companionway alarm.
Note: I can take no credit for this alarm. It was on the boat when we purchased it. We do like it though, and use it every night.
- Fishing line
- Tiny on/off toggle switch
- 12V relay
- 12V siren
The fishing line is strung across the companionway door, and is all but invisible if you don’t know that it is there. One end is fixed and the other end is attached to the toggle switch. The switch is left in the off position (open), and is aligned such that when someone presses against the fishing line, the toggle is pulled, turning the switch on (closing the switch).
When the switch is closed, the relay is energized, providing power to the siren. In our case, the relay and siren are located inside a cabinet, adjacent to the companionway.
Does the alarm work? Believe it! Even though no one has attempted to break into our boat, I can say that it works with confidence because both Rebecca and I, having forgotten that the alarm was armed, have set it off. The siren in our system is definitely loud enough to alert anyone on board that someone is at the companionway, and hopefully, also loud enough to scare away any tiefs. The only thing that would make this better is if instead of triggering a siren, the alarm set off a recording of a bunch of dogs aggressively barking!