🔍 Key Concepts

• GMDSS Sea Areas A1, A2, A3 – know how each is defined (VHF-DSC, MF-DSC, satellite). • The actual radio coverage along the U.S. East Coast, around Florida, and along the Gulf Coast. • How Sea Areas are defined by coverage, not by specific geographic locations or voyage names.

💭 Think About

• First, recall the exact definitions of Sea Areas A1, A2, and A3 in terms of which DSC-equipped coast stations (VHF or MF) or systems (satellite) cover them. • Then picture a voyage hugging the U.S. coastline from Miami, around the Florida Keys, and across the Gulf of Mexico to Houston – would the ship always be under VHF-DSC coverage, or might it move beyond it? • Ask yourself: if a ship sails farther offshore to take a more direct route, how would that change which Sea Areas it could enter based on the range of VHF and MF coast stations?

✅ Before You Answer

• Verify how Sea Area A1 is defined: within range of at least one VHF-DSC coast station (continuous alerting). • Verify how Sea Area A2 is defined: outside A1 but within range of an MF-DSC coast station. • Verify how Sea Area A3 is defined: outside A1 and A2, but within INMARSAT satellite coverage – and consider whether a U.S. coastal/Gulf route could reach that condition depending on how far offshore the vessel chooses to sail.