🔍 Key Concepts

• 46 CFR requirements for lifejacket (PFD) lights • Difference between replaceable vs non‑replaceable power sources • How manufacturers mark service life / expiration dates on lifesaving appliances

💭 Think About

• Ask yourself: Does the Coast Guard usually require replacement on a fixed time from installation, or by a date determined by the manufacturer? • Think about how practical it would be for a vessel to track installation dates for every single light versus using information already printed on the device. • Consider what happens if a light sits in storage for a long time before being installed—would a rule based only on ‘after initial installation’ make safety sense?

✅ Before You Answer

• Check what 46 CFR Part 161 (lifesaving equipment) says about ‘service life’ and ‘expiration date’ for lifejacket lights. • Verify whether the term used in the regulation is tied to calendar time after installation or to a date marked by the manufacturer. • Confirm that the requirement discussed is specific to non-replaceable power sources (sealed battery units), not lights with changeable batteries.