@seawomanmarine: Sea Areas A1, A2, A3, and A4 (GMDSS) The Global Maritime Distress and Safety System (GMDSS) divides the world’s oceans into four Sea Areas (A1–A4) based on the availability of shore-based radio stations and satellite communication. These areas ensure that ships can send distress alerts and maintain reliable communications while at sea. ✅Sea Area A1 * Located within the coverage of at least one VHF coast radio station with continuous DSC (Digital Selective Calling) watch. * Typical range: 20–30 nautical miles from the coast. * Uses VHF radio (156–174 MHz). * Commonly found in coastal waters where communication with shore is readily available. ✅Sea Area A2 * Extends beyond A1 but remains within the coverage of MF coast radio stations with continuous DSC watch. * Typical range: 150–300 nautical miles from shore. * Uses MF radio (525–1606.5 kHz). * Provides reliable communication for vessels operating farther offshore. ✅Sea Area A3 * Covers waters outside A1 and A2 but within the coverage of Inmarsat geostationary satellites (approximately between 70°N and 70°S). * Uses satellite communication for distress, safety, and routine ship-to-shore communications. * Encompasses the majority of the world’s commercial shipping routes. ✅Sea Area A4 * Includes polar regions outside the coverage of Inmarsat satellites. * Covers areas north of 70°N and south of 70°S. * Ships rely on HF radio and other satellite systems capable of operating in polar regions for distress and safety communications. ✅Takeaway Understanding Sea Areas A1–A4 is essential for seafarers because each area determines the communication equipment required on board under GMDSS regulations. This ensures that ships can always send distress alerts, receive Maritime Safety Information (MSI), and maintain communication wherever they operate. #w4ypoints #basicthingstoknow #maritimeknowledge

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Monday 27 July 2026 21:08:02 GMT