Effective marine radio communication relies on structured standard operating procedures (SOPs). Below is a comprehensive guide covering radio emergency calls, operational routing (VHF vs. landline in Southern California), and Digital Selective Calling (DSC) / Maritime Mobile Service Identity (MMSI) configuration.

1. Line-by-Line VHF Spoken Scripts

Standard radio procedures dictate repeating primary keywords three times to ensure clarity over static or poor signal conditions. When broadcasting, speak slowly, clearly, and pronounce numbers individually (e.g., “One-Eight-Zero” instead of “One-Eighty”).

Priority 1: MAYDAY (Distress)

Use Case: Immediate, grave threat to life or the vessel (e.g., active fire, sinking, severe medical emergency, collision taking on unmanageable water).

Broadcast Protocol

  • Channel: VHF Channel 16
  • Power Output: High Power (25 Watts)

Line-by-Line Script

“MAYDAY, MAYDAY, MAYDAY.”

“ALL STATIONS, ALL STATIONS, ALL STATIONS.” (or “UNITED STATES COAST GUARD, UNITED STATES COAST GUARD, UNITED STATES COAST GUARD”)

“THIS IS MOTOR VESSEL BLUE HORIZON, MOTOR VESSEL BLUE HORIZON, MOTOR VESSEL BLUE HORIZON.”

“CALL SIGN: W D C ONE TWO THREE FOUR.”

“MMSI: THREE SIX SIX NINE EIGHT SEVEN SIX FIVE FOUR.”

“MAYDAY, MOTOR VESSEL BLUE HORIZON.”

“POSITION: THREE THREE DEGREES FOUR TWO POINT FIVE MINUTES NORTH, ONE ONE EIGHT DEGREES ONE FIVE POINT TWO MINUTES WEST.” (Or: “BEARING ONE EIGHT ZERO DEGREES MAGNETIC, THREE POINT FIVE NAUTICAL MILES SOUTH OF POINT FERMIN LIGHT.”)

“NATURE OF DISTRESS: WE ARE TAKING ON WATER IN THE ENGINE ROOM AND LOSING POWER FAST.”

“ASSISTANCE REQUIRED: IMMEDIATE ENGINE PUMPING AND TOW ASSISTANCE REQUIRED.”

“PERSONS ON BOARD: FOUR PERSONS ON BOARD.”

“VESSEL DESCRIPTION: THIRTY-SIX FOOT CABIN CRUISER, WHITE HULL, BLUE CANVAS TOP.”

“SAFETY EQUIPMENT: ALL PASSENGERS WEARING LIFE JACKETS, DISTRESS FLARES AND EPIRB ON BOARD.”

“OVER.”

Priority 2: PAN-PAN (Urgency)

Use Case: Urgent situations regarding the safety of a vessel or person, but without immediate, grave danger to life or structural loss of the vessel (e.g., loss of steering in open water away from hazards, engine failure in calm seas, non-life-threatening injury).

Broadcast Protocol

  • Channel: VHF Channel 16
  • Power Output: High Power (25 Watts)

Line-by-Line Script

“PAN-PAN, PAN-PAN, PAN-PAN.”

“ALL STATIONS, ALL STATIONS, ALL STATIONS.”

“THIS IS SAILING VESSEL WIND DANCER, SAILING VESSEL WIND DANCER, SAILING VESSEL WIND DANCER.”

“CALL SIGN: K X Y FIVE SIX SEVEN EIGHT.”

“MMSI: THREE SIX SIX EIGHT SEVEN SIX FIVE FOUR THREE.”

“PAN-PAN, SAILING VESSEL WIND DANCER.”

“POSITION: THREE TWO DEGREES FOUR ZERO POINT ZERO MINUTES NORTH, ONE ONE SEVEN DEGREES TWO ZERO POINT FIVE MINUTES WEST.” (Or: “FIVE NAUTICAL MILES WEST OF MISSION BAY ENTRANCE.”)

“NATURE OF URGENCY: DISABLED ENGINE, SHREDDED MAINSAIL, DRIFTING AT TWO KNOTS TOWARD OPEN OCEAN. NO IMMEDIATE DANGER, BUT UNABLE TO MAKE WAY.”

“ASSISTANCE REQUIRED: REQUEST COMMERCIAL TOW OR VESSEL ASSISTANCE TO TOW TO MISSION BAY.”

“PERSONS ON BOARD: TWO PERSONS ON BOARD.”

“VESSEL DESCRIPTION: THIRTY-TWO FOOT CATALINA SLOOP, WHITE HULL, RED STRIPE.”

“OVER.”

Priority 3: SECURITE (Safety)

Use Case: Navigational safety warnings, severe sudden weather updates, submerged hazards/debris, malfunctioning aids to navigation, or heavy commercial traffic maneuvering in narrow channels.

Broadcast Protocol

  1. Announce initial broadcast on VHF Channel 16.
  2. Shift the audience to a non-emergency working channel (e.g., VHF Channel 22A / 1022 or Channel 09) to deliver the full message.

Step 1: Initial Announcement on Channel 16

“SECURITE, SECURITE, SECURITE.”

“ALL STATIONS, ALL STATIONS, ALL STATIONS.”

“THIS IS MOTOR VESSEL SEA SCOUT, MOTOR VESSEL SEA SCOUT, MOTOR VESSEL SEA SCOUT.”

“FOR A SAFETY MESSAGE REGARDING A SUBMERGED NAVIGATION HAZARD OFF POINT LOMA, PLEASE SWITCH AND LISTEN TO VHF CHANNEL TWO TWO ALPHA.”

“OUT.”

(Switch radio immediately to Channel 22A / 1022)

Step 2: Full Safety Message on Channel 22A (1022)

“SECURITE, SECURITE, SECURITE.”

“ALL STATIONS, ALL STATIONS, ALL STATIONS.”

“THIS IS MOTOR VESSEL SEA SCOUT, SEA SCOUT, SEA SCOUT.”

“POSITION: OBSERVED AT THREE TWO DEGREES THREE NINE POINT EIGHT MINUTES NORTH, ONE ONE SEVEN DEGREES ONE FOUR POINT FIVE MINUTES WEST.”

“HAZARD: SEMI-SUBMERGED TWENTY-FOOT SHIPPING CONTAINER DRIFTING SOUTH-SOUTHWEST AT ONE POINT FIVE KNOTS. POSE HIGH RISK TO SMALL CRAFT.”

“DATE/TIME: SEPTEMBER FIRST, ONE ZERO ZERO ZERO HOURS LOCAL.”

“VESSEL SEA SCOUT STANDING BY ON CHANNEL ONE SIX.”

“OUT.”

2. Communication Routing: VHF Channel 16 vs. USCG Landline Numbers

Choosing the appropriate communication medium depends on distance off shore, line-of-sight constraints, urgency, and privacy considerations.


When to Use VHF Channel 16

VHF Channel 16 is an open, monitored emergency and calling frequency. Use Channel 16 when:

  1. Active Distress or Urgency (MAYDAY / PAN-PAN): Nearby mariners listening on Channel 16 can often reach your position faster than a Coast Guard cutter or helicopter can deploy.
  2. Line-of-Sight Coverage: VHF radio signals work via line-of-sight. The USCG Rescue 21 system uses tall coastal towers that provide robust coverage out to 20+ nautical miles offshore, often outperforming cellular networks.
  3. Broadcasting Navigational Safety Warnings: Securite broadcasts must reach all vessels in the immediate vicinity.
  4. Initial Hailing of Coastal Vessels / USCG Stations: Channel 16 serves as the international calling frequency before moving to an operational channel (e.g., 68, 69, 71, 72, 22A).

When to Use Direct Landline Numbers

Cellular connectivity near the coast can supplement VHF radio. Use landline phone numbers when:

  1. Cellular Signal is Available & VHF is Inoperable: In the event of main battery failure, submerged radio units, or dismasting (losing the VHF antenna).
  2. Filing / Canceling Float Plans: Non-emergency communications with Sector Command Centers regarding missing vessels or extended arrival times.
  3. Reporting Non-Urgent Marine Issues: Informing authorities of drifting uncrewed kayaks, non-hazardous debris, broken buoys, or oil sheens without cluttering Channel 16.
  4. Sensitive Security / Law Enforcement Reports: Reporting suspicious maritime activity, smuggling, or security concerns requiring non-public voice channels.
  5. Direct Pre-Trip Operational Coordination: Requesting bridge openings, checking harbor entry status, or verifying military zone closures before leaving the dock.

USCG Sector Command Center Contact Details

Keep these direct command center emergency lines programmed into mobile devices or posted near the helm station:

1. USCG Sector Los Angeles-Long Beach (Sector LA/LB)

  • Operational Area: Point Conception south to Dana Point (includes LA/LB Harbors, Santa Barbara Channel, Channel Islands, Santa Catalina Island).
  • 24/7 Sector Command Center Emergency Line: (310) 521-3801
  • Toll-Free Emergency Line: (800) 221-8724
  • VHF Monitoring: Channel 16 (Call Sign: Coast Guard Sector LA-Long Beach)

2. USCG Sector San Diego

  • Operational Area: Dana Point south to the US/Mexico Border, extending inland to regional waterways (includes San Diego Bay, Mission Bay, Oceanside Harbor, Salton Sea).
  • 24/7 Sector Command Center Line: (619) 278-7033 (or 1-800-854-9834)
  • VHF Monitoring: Channel 16 (Call Sign: Coast Guard Sector San Diego)

3. Digital Selective Calling (DSC) & MMSI Setup

Digital Selective Calling (DSC) transforms a standard VHF marine radio into an automated emergency beacon and targeted calling system.


When activated, a DSC emergency broadcast transmits your vessel’s identity, exact GPS coordinates, and distress nature digitally on VHF Channel 70, triggering automatic alarms on all DSC-equipped vessels and USCG shore installations within range.

Understanding MMSI Numbers

A Maritime Mobile Service Identity (MMSI) is a unique 9-digit number assigned to a specific vessel. It functions like a maritime telephone number and is hardcoded into your VHF DSC radio, AIS transceiver, and EPIRB.

  • Format for US Flagged Non-Commercial Vessels: Starts with the US country code (MID – Maritime Identification Digits: 338, 366, 367, 368, 369), followed by 6 unique digits.
    • Example: 366987654

Step-by-Step MMSI & DSC Setup Protocol

<Sequence>
  <Step title="Determine Licensing Requirements" subtitle="US Coastal vs. International Travel">
    Identify whether your vessel needs an FCC station license or a free registration:
    * **US Domestic Waters Only:** If operating domestically without visiting foreign ports or using HF/SSB radios, obtain an MMSI for free or low cost through authorized agents like **BoatUS**, **Sea Tow**, or **United States Power Squadrons (USPS)**.
    * **International Voyages:** If sailing to Mexico (e.g., Baja California), Canada, or any foreign port, obtain an official **Ship Station License** and MMSI directly through the **FCC Universal Licensing System (ULS)**. Domestic non-FCC MMSIs are not recognized in foreign SAR databases.
  </Step>

  <Step title="Register and Obtain the 9-Digit MMSI">
    Log into your chosen provider (BoatUS or FCC ULS) and enter accurate vessel data:
    * Vessel name, overall length, hull color, make/model.
    * Primary homeport and registration/documentation number.
    * 24/7 emergency shore contact information (next of kin/float plan holders).
    * Save your registration certificate in your vessel's logbook.
  </Step>

  <Step title="Connect GPS / NMEA Data Stream">
    DSC distress calls require position coordinates to function effectively:
    * **Built-in GPS Radios:** Ensure internal GPS fixes are active (verify latitude/longitude displays on the radio screen).
    * **External GPS Connection:** Connect your VHF radio to your chartplotter using a **NMEA 0183** (bare wire pairs: NMEA Out(+) from GPS to NMEA In(+) on VHF) or **NMEA 2000** network backbone connection.
    * Confirm that live coordinates display on the radio display.
  </Step>

  <Step title="Program MMSI into the VHF Unit">
    * Access your radio's setup menu: `MENU` -> `DSC SETUP` -> `MMSI INPUT`.
    * Enter the 9-digit MMSI number carefully.
    * Re-enter the MMSI when prompted to confirm.
    * **Critical Warning:** VHF manufacturers restrict MMSI programming to **one or two user attempts**. Entering an incorrect number twice will lock the radio, requiring factory servicing to clear.
  </Step>

  <Step title="Perform a Non-Emergency DSC Test Call">
    **NEVER press the RED DISTRESS BUTTON to test your system.**
    * Request a test call using the **US Coast Guard Automated DSC Test System** or place an **Individual Test Call** to a nearby vessel's MMSI.
    * Select `DSC CALL` -> `INDIVIDUAL` -> Enter Target MMSI -> Select Working Channel -> Transmit.
    * Confirm the target radio rings and returns an automated acknowledgment.
  </Step>
</Sequence>

How to Execute an Automated DSC Emergency Activation

If an emergency occurs:

  1. Lift the Protective Cover: Flip up the red spring-loaded cover over the DISTRESS button on the VHF radio.
  2. Select Distress Nature (Optional): If time permits, scroll to select the specific emergency (Undesignated, Fire, Flooding, Collision, Grounding, Capsizing, Abandoning Ship).
  3. Press and Hold: Press and hold the DISTRESS button for 3 to 5 continuous seconds. The radio will count down with an audible alert.
  4. Broadcast: The radio automatically locks to maximum output (25W) and sends the digital alert on Channel 70.
  5. Follow Up with Voice: Once the digital transmission completes, the radio switches automatically to VHF Channel 16. Pick up the microphone and broadcast the spoken MAYDAY script detailed in Section 1.

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