What piece of equipment on a boat is most important in preventing propeller

Ignition safety switch
The ignition safety switch, often known as the engine cut-off switch, is the most critical piece of equipment for preventing propeller strike injuries. The purpose of this device is to turn off the boat engine immediately so the propeller will be halted and an accident can be avoided.

The characteristics of groundwater is said to be: are weak turbiditya constant temperaturechemical composition and almost overall absence of oxygen.

It's have to be 12 or idk