Final answer:
The limitation on overwater operations with only life jackets on board is that they do not provide enough buoyancy to keep a person afloat for an extended period of time. Additional safety equipment like life rafts or lifeboats should be used to increase the chances of survival and rescue.
Step-by-step explanation:
The limitation on overwater operations with only life jackets on board is that life jackets do not provide enough buoyancy to keep a person afloat in open water for an extended period of time. Life jackets are designed to keep a person's head above water and provide some support, but they cannot prevent a person from becoming fatigued or hypothermic if they are in the water for a long time.
In situations where overwater operations are required, it is important to have additional safety equipment such as life rafts or lifeboats that can provide more buoyancy and protection against the elements. These additional safety measures can increase the chances of survival and rescue in case of an emergency.