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.
Recreational
Sierra
MMSI 367612940 · Call sign WDH3978
Not yet on Master's MateType
Recreational
Flag
USALength
11.9 m
Beam
3.7 m
Draft
3.2 m
Call sign
WDH3978
Official No.
652434
AIS reports
1
Sierra is a cruising boat registered in the United States, 11.9 metres from stem to stern. Sierra has a beam of 3.7 m and a 3.2-metre draft. On AIS she appears as MMSI 367612940, call sign WDH3978. Sierra can be part of the Master's Mate Safety Initiative Network at no cost — a community watch that never sleeps.
Free forever · No credit card · for recreational captains
Keep Sierra looked after — even when you’re not aboard.
Anchor alarms that wake you, a live camera at the dock, and weather you can trust before every run.
Look after her — claim free →Takes 60 seconds · Your data stays yours · Built by cruisers, for cruisers
Wherever Sierra 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 · for recreational captains
The most powerful cruising platform ever built — yours, free.
Joining the Safety Initiative Network doesn't just put Sierra 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.
Onboard Cameras
Watch your boat from anywhere — live feeds and 24h recording, straight from your gateway.
Weather & Routing
GRIB wind, swell & current on the chart. Plan passages with ETA-calibrated forecasts per leg.
Worldwide Charts
Navionics-grade vector charts, satellite & raster overlays, online or off. Your whole cruising ground.
Systems Monitoring
Batteries, bilge, tanks, Victron & NMEA 2000 telemetry — your whole boat on one dashboard.
Live AIS & Traffic
See every vessel around you in real time. Closest-approach warnings before they matter.
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 Sierra and switch it all on
Free to join · nothing to install to start · cancel anytime
About Sierra
What kind of vessel is Sierra?
Sierra is a Recreational flagged to United States of America.
What is Sierra's MMSI?
Sierra's MMSI is 367612940. Call sign WDH3978.
How big is Sierra?
Sierra is about 11.9 m long, 3.7 m on the beam, drawing 3.2 m.
Is Sierra on the Master's Mate Safety Initiative Network?
Not yet. If Sierra is your boat, you can claim it free and join the Master's Mate Safety Initiative Network (MMSIn).
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