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.
Offshore Supply Vessel
HOS Gemstone
MMSI 369279000 · Call sign WDB4055
Not yet on Master's MateType
Offshore Supply Vessel
Flag
USALength
67.6 m
Beam
16.5 m
Draft
5.5 m
Call sign
WDB4055
IMO
9270995
Official No.
1141952
AIS reports
1
HOS Gemstone is an American service vessel, measuring 67.6 metres. She carries a beam measuring 16.5 metres and a 5.5 m draft. Her papers read MMSI 369279000, call sign WDB4055, IMO 9270995. Working vessels like HOS Gemstone are never truly alone on the Master's Mate Safety Initiative Network — free, with a fleet on watch.
Free forever · No credit card · for working boats
Built for boats that work — like HOS Gemstone.
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 HOS Gemstone 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 HOS Gemstone 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 HOS Gemstone and switch it all on
Free to join · nothing to install to start · cancel anytime
About HOS Gemstone
What kind of vessel is HOS Gemstone?
HOS Gemstone is a Offshore Supply Vessel flagged to United States of America.
What is HOS Gemstone's MMSI?
HOS Gemstone's MMSI is 369279000. Call sign WDB4055. IMO 9270995.
How big is HOS Gemstone?
HOS Gemstone is about 67.6 m long, 16.5 m on the beam, drawing 5.5 m.
Is HOS Gemstone on the Master's Mate Safety Initiative Network?
Not yet. If HOS Gemstone is your boat, you can claim it free and join the Master's Mate Safety Initiative Network (MMSIn).
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