A regulation in 2021 requires all boats under 26 feet to have a cutoff switch
Back in April of 2021, a new law took effect that requires power boats and personal watercraft under 26' to have a kill switch. Many boats are grandfathered in, but that list continues to be reduced each year.
The purpose of the law is to reduce runaway boats and prop strikes. The operator is supposed to be wearing a lanyard (or an electronic kill switch fob) to kill the engine if they are thrown off the vessel. I'm most familiar with them on dinghy outboards and wave runners.
My dinghy has an older Mercury two-stroke 9.8hp outboard. It has a switch to kill the engine, but not one to accommodate a lanyard that would stop it if the operator (me, in this case!) fell off. After reading an article by the Boat Galley lady, Carolyn, about how a friend escaped grave injury when their dinghy got away and tried to run them down, I decided to install a kill switch with a lanyard.
By the way, there is a template in BoatProject called "Kill Switch Install Outboard" that details the process and shows the replacement switch.
But the general process for me was this:
- Research - find some kill switch/lanyard combos and get the specs.
- Measure - I put a caliper on the stem of the existing switch to see how big the hole was in the housing to make sure I got a replacement that would not (hopefully) require drilling.
- Figure out what kind of switch - There are two types of switches; one that closes a circuit when the lanyard is pulled, and one that opens the circuit when the lanyard is pulled. The switch that closes when the lanyard is pulled is most common. This was curious to me. I figured you would want to break the electric to the spark plug; instead, the switch closes and in effect, shorts the circuit denying the spark plug of electricity. To know for sure, I put a meter at each end of the existing button and watched what happened when I pressed it (motor not running of course). I found that with the meter on the button unpressed, the circuit was open ie. no electricity was going through the switch. When I pushed the button (which is how I currently kill the engine), the meter showed continuity, ie. a closed circuit. So my engine took the common type of switch; one that closes a circuit to stop the engine.
- Check your new switch - just to be sure, I put the lanyard on the switch and took a meter reading. Switch was open; no continuity. When I removed the lanyard (ie. I fell off and the lanyard came with me), the switch showed continuity ie it was closed. It should work as intended.
- Wire the new switch - I could not for the life of me loosen the screws that the ends of the wires attached, so I cut them such that I could crimp on the new switch. At least I didn't have to worry about reconnecting to the wrong place!
- Test - First time firing up the engine, pull the lanyard and make sure the engine stops.