Professional Military Knowledge Eligibility Exam (PMK-EE) E4 Seamanship Practice Exam

The correct action to take before discharging a CO2 portable extinguisher is to remove the safety pin. This is a crucial first step because the safety pin prevents accidental discharge of the extinguisher. Once the safety pin is removed, the operator can safely aim and discharge the extinguisher at the fire.

Understanding the operation of a CO2 extinguisher is vital for effective fire response. The safety pin is designed to keep the handle locked, ensuring that the extinguisher isn’t activated unintentionally. After the safety pin is removed, the user can squeeze the handle, which releases the pressurized CO2 to extinguish the fire.

The other options involve actions that do not directly prepare the extinguisher for use, such as placing it on the deck or checking the pressure gauge, which, while important for maintenance and operational readiness, are not immediate prerequisites for discharging the extinguisher in an emergency situation.