U.S. Coast Guard – Choppy Seas Boating Resources

Help them help you provide a safe and fun time on the water.

Understanding Coast Guard operational structure and marine communication protocols is critical for maritime safety.

1. U.S. Coast Guard Sector Organization

The U.S. Coast Guard organizes its operations into Districts, which are subdivided into Sectors. A Sector serves as the central operational hub for marine safety, environmental protection, law enforcement, and search and rescue (SAR) within a specific geographic area.

Oak and Liberty+ 1

                 Coast Guard Sector
                         │
    ┌────────────────────┼────────────────────┐
    ▼                    ▼                    ▼
Command Center   Prevention Division   Response Division
(24/7 Monitoring) (Safety & Inspection) (SAR & Enforcement)
                         │                    │
                         ├────────────────────┤
                         ▼                    ▼
                   Coast Guard           Air Stations
                   Small Stations        & Cutters

Sector Command Center (SCC): The 24/7 nerve center. It monitors radio frequencies (like VHF Channel 16), coordinates emergency responses, tracks vessels, and directs rescue operations.
Response Division: Oversees incident response. Under this division are:
- Coast Guard Small Boat Stations: Frontline units located along coasts and waterways that launch response boats (e.g., 45-foot Response Boats or 47-foot Motor Lifeboats) for immediate SAR and enforcement.
- Air Stations & Cutters: Provides long-range helicopter/fixed-wing aircraft support and offshore patrol vessels.
Prevention Division: Handles vessel safety inspections, harbor safety, navigation aids, and accident investigations.
Logistics & Planning: Maintains systems, equipment, and readiness across the sector.

2. Communication Devices Used to Contact the Coast Guard

Boaters rely on several primary tools to broadcast distress or request aid:

Device	Primary Use	Coast Guard Integration	Key Features
VHF Marine Radio (Fixed or Handheld)	Primary short-range emergency & operational comms.	Monitored 24/7 on Channel 16 via Rescue 21 infrastructure.	Line-of-sight range (~5–20 miles). Standard tool for voice calls.
VHF DSC (Digital Selective Calling)	Instant digital distress alert.	Tied directly to Rescue 21 towers; transmits precise location if linked to GPS.	Transmits an automated distress signal with your MMSI number at the push of a red button.
EPIRB (Emergency Position Indicating Radio Beacon)	Vessel-level emergency locator beacon.	Triggers the Cospas-Sarsat satellite system, relaying alert to the USCG SAR Coordinator.	Broadcasts on 406 MHz; float-free models deploy automatically if the vessel sinks.
PLB (Personal Locator Beacon)	Individual emergency beacon carried by a person.	Satellite-routed to emergency responders, including USCG.	Manually activated; tied to an individual rather than a registered boat.
Satellite Messengers / Phones (e.g., Garmin inReach, ZOLEO)	Off-grid text & SOS calling.	SOS relays through emergency centers (e.g., IERCC) to the nearest USCG Command Center.	Works well beyond VHF line-of-sight.
Cell Phone	Supplemental communication close to shore.	Reaches USCG via local sector numbers or 911 relay.	Secondary only: Cell coverage is unreliable offshore and does not alert nearby mariners who could assist.

3. Marine Urgency & Distress Calls: Mayday vs. Pan-Pan vs. Sécurité

International maritime law defines three standard radio call formats based on urgency:

MAYDAY (Distress)

Meaning: Derived from French venez m’aider (“come help me”). Used only when there is grave and immediate danger to life or the vessel. Wikipedia+ 1
Examples: Vessel taking on water rapidly, active uncontrolled fire, medical emergency with impending loss of life, or vessel sinking. Hanham Insurance Agency

PAN-PAN (Urgency)

Meaning: Derived from French panne (“breakdown”). Used when a situation is urgent, but does not pose an immediate threat to life or vessel integrity. Wikipedia+ 1
Examples: Total engine failure in open water with no immediate hazard, a controllable leak, or a non-life-threatening medical emergency (e.g., broken leg).

SÉCURITÉ (Safety)

Meaning: Derived from French sécurité (“safety”). Used to transmit important navigation warnings or severe weather alerts.
Examples: Reporting floating shipping containers, submerged debris, broken aids to navigation, or sudden severe weather warnings.

4. Proper Terminology & Transmission Format

When making an emergency voice transmission on VHF Channel 16, follow standard maritime radio protocol to ensure your message is understood quickly.

Step-by-Step Mayday Format

Switch to Channel 16.
Distress Call: Say “MAYDAY, MAYDAY, MAYDAY”. Hanham Insurance Agency
Station Identification: Say “THIS IS [Vessel Name / Call Sign]” three times.
Position: Give your GPS coordinates (Latitude/Longitude) or a precise range/bearing from a known landmark.
Nature of Distress: State clearly what is happening (e.g., “Taking on water, pumps overwhelmed”).
Assistance Required: State what help you need (e.g., “Request immediate evacuation”).
Vessel Details & POB: State the number of People On Board (POB), vessel description (length, hull color, type), and safety gear on hand (e.g., liferaft deployed, wearing PFDs).
Over: End with “OVER” to invite a reply.

Example Transmission Script: Mayday (Distress signal)

“MAYDAY, MAYDAY, MAYDAY.

THIS IS SEA BREEZE, SEA BREEZE, SEA BREEZE (Call Sign WXZ1234).

MAYDAY, SEA BREEZE.

POSITION: 25 DEGREES 42 MINUTES NORTH, 080 DEGREES 08 MINUTES WEST, APPROXIMATELY 4 MILES EAST OF MIAMI LIGHT.

WE ARE TAKING ON WATER FAST AND PREPARING TO ABANDON SHIP.

REQUIRE IMMEDIATE SEARCH AND RESCUE ASSISTANCE.

4 PEOPLE ON BOARD, ALL WEARING LIFE JACKETS, DEPLOYING 6-PERSON LIFE RAFT.

VESSEL IS A 32-FOOT WHITE HULL POWERBOAT WITH A BLUE CANVAS TOP.

OVER.”

Example Transmission Script: PAN-PAN (Urgency Signal)

Use PAN-PAN three times when there is an urgent safety concern regarding a vessel or person, but there is no immediate threat to life or property.

“PAN-PAN, PAN-PAN, PAN-PAN.

ALL STATIONS, ALL STATIONS, ALL STATIONS.

THIS IS BLUE FIN, BLUE FIN, BLUE FIN (Call Sign WXY5678).

POSITION: 3 GALLON LEDGE, APPROXIMATELY 2 MILES SOUTH OF BOOTHBAY HARBOR.

WE HAVE SUFFERED TOTAL ENGINE FAILURE AND ARE DRIFTING TOWARDS ROCKY SHOALS.

REQUIRE TOWING ASSISTANCE.

3 PEOPLE ON BOARD, ALL WEARING LIFE JACKETS. NO INJURIES.

VESSEL IS A 24-FOOT YELLOW HULL CENTER CONSOLE.

OVER.”

Example Transmission Script: SÉCURITÉ (Safety Signal)

Use SÉCURITÉ (pronounced Say-cure-ee-tay) three times to broadcast navigation hazards, weather warnings, or debris reports.

“SÉCURITÉ, SÉCURITÉ, SÉCURITÉ.

ALL STATIONS, ALL STATIONS, ALL STATIONS.

THIS IS FREEDOM, FREEDOM, FREEDOM (Call Sign WZA9012).

POSITION: 1 MILE WEST OF BUOY 14 IN THE MAIN CHANNEL.

WE HAVE SIGHTED A HALF-SUBMERGED SHIPPING CONTAINER DRIFTING EAST IN THE NAVIGATION CHANNEL, POSING A SEVERE HAZARD TO NAVIGATION.

ALL VESSELS IN THE AREA PLEASE NAVIGATE WITH CAUTION.

OUT.”

Standard Radio Procedural Words (Prowords)

OVER: I have finished speaking and expect a reply.
OUT: I have finished speaking and no reply is expected. (Never say “Over and Out” together).
ROGER: Message received and understood.
WILCO: Message understood; will comply with instructions.
SILENCE MAYDAY (pronounced Seelonnss Mayday): Announced by the Coast Guard or controlling station to command all other vessels to keep off the channel during active distress communications.
SILENCE FINI (pronounced Seelonnss Fee-nee): Broadcast by the Coast Guard to signal that emergency radio traffic has concluded and Channel 16 is clear for normal operations.