Propeller strikes are one of the most devastating types of boating accidents, often resulting in severe lacerations, amputations, or fatalities. Understanding the equipment designed to prevent these injuries could save lives on the water.
The Engine Cut-Off Switch (ECOS)
The engine cut-off switch — also known as a kill switch or engine cut-off device — is the single most important piece of equipment for preventing propeller strike injuries. When the operator is thrown from the helm or falls overboard, the ECOS immediately shuts down the engine, stopping the propeller before it can strike anyone in the water.
How It Works
The ECOS consists of a lanyard attached to the operator and connected to a switch on the console. If the operator moves too far from the helm — whether from a fall, a sharp turn, or being ejected — the lanyard pulls free and the engine cuts off instantly. Some modern boats use wireless fob-based systems that work on the same principle.
It's the Law
As of April 2021, federal law (the Dingell Act) requires operators of recreational vessels under 26 feet with an engine capable of 115 lbs of thrust to use an engine cut-off switch while on plane. Many states have adopted additional ECOS requirements.
Other Preventive Measures
While the ECOS is the most critical piece of equipment, other measures can also help reduce propeller strike risk:
Propeller guards: Physical cages around the propeller that prevent contact
Swim platform interlocks: Systems that disable the engine when the swim platform ladder is deployed
Operator awareness: Always keeping a headcount of passengers and maintaining a proper lookout
Posted warning labels: Clear signage near the stern and propeller area
The Bottom Line
No single piece of equipment replaces good judgment and safe boating practices. But if there's one thing every boater should use without exception, it's the engine cut-off switch. It takes two seconds to clip on, and it could prevent a tragedy.
