🔍 Key Concepts

• Small passenger vessel radio requirements in 46 CFR Subchapter T • GMDSS sea areas (A1, A2, A3) and how distance from nearest land relates to them • Differences between Inmarsat systems, MF-HF SSB, and aircraft emergency radios

💭 Think About

• How does sailing 20–150 nautical miles from land change the communication and distress alerting needs compared with staying close to shore? • Which option provides maritime long‑range digital distress alerting and basic text messaging suitable for small passenger vessels, rather than aviation use or large‑ship systems? • Think about which equipment is commonly mandated for ships operating beyond VHF range but not necessarily on long ocean passages.

✅ Before You Answer

• Verify which system is specifically part of GMDSS carriage requirements for sea area A2/A3 for smaller vessels, where applicable. • Check which choice is intended for aircraft, not vessels, and eliminate it. • Confirm which system is a full‑size, higher‑cost installation mainly required on larger SOLAS ships, and which one is the more compact, text‑based maritime satellite option.