What is the primary disadvantage of the Type IV throwable device?

The primary disadvantage of the Type IV throwable device is that it cannot be worn. Unlike personal flotation devices (PFDs) designed to be worn, such as Type I, II, and III PFDs, the Type IV is intended to be thrown to someone in distress and is not designed to be worn while boating. This means that in an emergency situation, the effectiveness of the device relies on someone being able to reach it and throw it to a person in the water, rather than providing continuous buoyancy to the wearer.

In contrast, other types of flotation devices that can be worn provide a more proactive approach to safety, as they keep the wearer afloat without delay. It's essential for boaters to always have a quick and accessible means of flotation available, particularly for situations where immediate assistance is crucial. Understanding this limitation of the Type IV device highlights the importance of having the right type of flotation device for varying circumstances on the water.