PST-L2.1

Lifejackets, immersion suits and thermal protection

The equipment you wear and carry into the water is your first line of survival, and knowing how to use it correctly is essential. This lesson covers lifejackets, immersion suits and thermal protective aids.

What keeps you afloat and warm

  • The lifejacket keeps you afloat and, correctly designed and worn, turns an unconscious person face-up.
  • The immersion suit insulates against the cold of the water and greatly extends survival time.
  • The thermal protective aid (TPA) is a bag or suit that reduces heat loss in a survival craft.
  • Know how to don each quickly and correctly, and check the fastenings and the light.

A lifejacket keeps you afloat with your airway clear of the water, and a good one will right and support an exhausted or unconscious wearer face-up — which is why it must be worn and fastened correctly, not just carried. In cold water the immersion suit is what buys survival time, insulating the body against the rapid heat loss that would otherwise cause hypothermia in minutes. The seafarer must be able to don a lifejacket and immersion suit quickly and correctly, because in an abandonment there is no time to puzzle over the fastenings.

WARNING — A lifejacket only works if worn correctly An unfastened or wrongly worn lifejacket may not keep the airway clear or turn an unconscious wearer face-up. Fasten it fully every time, and check the light and whistle are there.

TIP — The immersion suit buys time in cold water In cold water, unprotected survival is measured in minutes; in an immersion suit it can be hours. Don the suit before entering the water whenever you can — it is the single biggest factor in cold-water survival.

Practice questions

5 questions
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A correctly designed and worn lifejacket will: (a) Sink an unconscious person (b) Turn an unconscious person face-up and keep the airway clear (c) Only help swimmers (d) Do nothing

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The immersion suit's main purpose is to: (a) Look bright (b) Insulate against cold water and extend survival time (c) Help you swim faster (d) Carry supplies

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A lifejacket must be: (a) Carried only (b) Worn and fully fastened (c) Left in the cabin (d) Inflated in the cabin

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In cold water, unprotected survival is measured in: (a) Days (b) Minutes (c) Weeks (d) Hours only

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A thermal protective aid (TPA) is used to: (a) Signal aircraft (b) Reduce heat loss in a survival craft (c) Catch water (d) Propel the raft

AI-drafted training content pending subject-matter-expert review. Figures indicative; verify against current provider materials.

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