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.
Towing Vessel
John Henry
MMSI 367753420 · Call sign WDI9913
Not yet on Master's MateType
Towing Vessel
Flag
USALength
19.9 m
Beam
5.9 m
Draft
2.9 m
Call sign
WDI9913
Official No.
616352
AIS reports
1
John Henry, an American work boat, measures 19.9 metres on deck. She has a beam of 5.9 m and a draft measuring 2.9 metres. On AIS she shows as MMSI 367753420, call sign WDI9913. Sign John Henry up free to the Master's Mate Safety Initiative Network and join a fleet that looks after its own.
Free forever · No credit card · for working boats
Built for boats that work — like John Henry.
Engine & systems telemetry, live AIS, weather and distress alerting for the vessels that earn their keep.
Rig her out — free →Takes 60 seconds · Your data stays yours · Built by cruisers, for cruisers
Wherever John Henry 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 working boats
The most powerful cruising platform ever built — yours, free.
Joining the Safety Initiative Network doesn't just put John Henry on the map. It hands you the full bridge:
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.
Weather & Routing
GRIB wind, swell & current on the chart. Plan passages with ETA-calibrated forecasts per leg.
Distress Mesh
Mayday & Pan-Pan that ripple out to nearby cruisers — a watch network that has your back.
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.
Onboard Cameras
Watch your boat from anywhere — live feeds and 24h recording, straight from your gateway.
Hail Any Captain
A verified captains directory + direct hailing. Reach the boat next to you, or across the bay.
Claim John Henry and switch it all on
Free to join · nothing to install to start · cancel anytime
About John Henry
What kind of vessel is John Henry?
John Henry is a Towing Vessel flagged to United States of America.
What is John Henry's MMSI?
John Henry's MMSI is 367753420. Call sign WDI9913.
How big is John Henry?
John Henry is about 19.9 m long, 5.9 m on the beam, drawing 2.9 m.
Is John Henry on the Master's Mate Safety Initiative Network?
Not yet. If John Henry is your boat, you can claim it free and join the Master's Mate Safety Initiative Network (MMSIn).
© 2026 Master’s Mate. All rights reserved.