Master's MateSafety Initiative Network
The Master's Mate Safety Initiative Network (MMSIn) — like AAA for the ocean, but free & community-driven. Cruisers keeping each other safe: anchor-drag & distress alerts, a verified captains directory, and a watch network that has your back.
Vessel
THUMPER IV
MMSI 366679980 · Call sign WCR9559
Not yet on Master's MateFlag
USACall sign
WCR9559
Official No.
VI6217TA
AIS reports
1
THUMPER IV is an American vessel. On AIS she shows as MMSI 366679980, call sign WCR9559. There's a place for THUMPER IV on the Master's Mate Safety Initiative Network — free, community-driven, like AAA for the ocean.
Free forever · No credit card
Is THUMPER IV your boat?
Your free claim unlocks the most powerful cruising platform ever built — anchor watch, worldwide charts, live AIS, weather routing, and a network of cruisers watching each other’s backs.
Claim this boat — free →Takes 60 seconds · Your data stays yours · Built by cruisers, for cruisers
Wherever THUMPER IV roams, you're never out there alone.
Thousands of cruisers on the Master's Mate Network — ready to help the moment something goes wrong.
Free with your claim
The most powerful cruising platform ever built — yours, free.
Joining the Safety Initiative Network doesn't just put THUMPER IV on the map. It hands you the full bridge:
Anchor Watch
GPS-precise drag alarms that actually wake you — and your whole crew. Sleep through the night.
Worldwide Charts
Navionics-grade vector charts, satellite & raster overlays, online or off. Your whole cruising ground.
Live AIS & Traffic
See every vessel around you in real time. Closest-approach warnings before they matter.
Weather & Routing
GRIB wind, swell & current on the chart. Plan passages with ETA-calibrated forecasts per leg.
Onboard Cameras
Watch your boat from anywhere — live feeds and 24h recording, straight from your gateway.
Systems Monitoring
Batteries, bilge, tanks, Victron & NMEA 2000 telemetry — your whole boat on one dashboard.
Distress Mesh
Mayday & Pan-Pan that ripple out to nearby cruisers — a watch network that has your back.
Hail Any Captain
A verified captains directory + direct hailing. Reach the boat next to you, or across the bay.
Claim THUMPER IV and switch it all on
Free to join · nothing to install to start · cancel anytime
About THUMPER IV
What kind of vessel is THUMPER IV?
THUMPER IV is a vessel flagged to United States of America.
What is THUMPER IV's MMSI?
THUMPER IV's MMSI is 366679980. Call sign WCR9559.
Is THUMPER IV on the Master's Mate Safety Initiative Network?
Not yet. If THUMPER IV is your boat, you can claim it free and join the Master's Mate Safety Initiative Network (MMSIn).
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