EPIRB Categories
Abbreviation: EPIRB
Two categories of 406 MHz EPIRB: Cat I auto-deploy and float-free; Cat II manual deployment.
In practice
Category I EPIRB is float-free with hydrostatic release on cargo ships; category II is manual-release for smaller vessels. The master verifies HRU service date is current; replacement every 2 years per manufacturer. Annual battery and self-test logged.
Regulatory detail & full definition
All maritime EPIRBs operate on 406 MHz (Cospas-Sarsat satellites) with a 121.5 MHz homer. Cat I is mandatory under SOLAS — float-free hydrostatic release at ~4 m depth. Cat II is supplementary or for non-SOLAS use. Battery life >= 48 h transmission. GPS-equipped EPIRBs (since ~2010) shorten location resolution from ~5 km to ~100 m.
Authoritative source: SOLAS Chapter III (Life-saving appliances) ↗
Related
Source: SOLAS Ch. III/4 + Ch. IV; IMO Res. A.810(19)
High confidence
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