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.
Tank Barge
S-40
U.S. Official No. 1231759
Not yet on Master's MateType
Tank Barge
Flag
USALength
45.7 m
Beam
16.5 m
Draft
4 m
First reported
Jun 2026
AIS reports
1
On the American registry, S-40 is a 45.7-metre tank ship. She has a beam measuring 16.5 metres and a draft measuring 4 metres. Find her under U.S. official number 1231759. Add S-40 to the Master's Mate Safety Initiative Network and share the water with a fleet that's paying attention — free.
Free forever · No credit card · for commercial operators
Eyes on S-40, around the clock.
Real-time AIS, full systems telemetry, distress alerting and worldwide charts — your hull on one dashboard, from anywhere.
Put her on the dashboard — free →Takes 60 seconds · Your data stays yours · Built by cruisers, for cruisers
Wherever S-40 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 commercial operators
The most powerful cruising platform ever built — yours, free.
Joining the Safety Initiative Network doesn't just put S-40 on the map. It hands you the full bridge:
Live AIS & Traffic
See every vessel around you in real time. Closest-approach warnings before they matter.
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.
Worldwide Charts
Navionics-grade vector charts, satellite & raster overlays, online or off. Your whole cruising ground.
Weather & Routing
GRIB wind, swell & current on the chart. Plan passages with ETA-calibrated forecasts per leg.
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.
Hail Any Captain
A verified captains directory + direct hailing. Reach the boat next to you, or across the bay.
Claim S-40 and switch it all on
Free to join · nothing to install to start · cancel anytime
About S-40
What kind of vessel is S-40?
S-40 is a Tank Barge flagged to United States of America.
What is S-40's U.S. Official No.?
S-40's U.S. Official No. is 1231759.
How big is S-40?
S-40 is about 45.7 m long, 16.5 m on the beam, drawing 4 m.
Is S-40 on the Master's Mate Safety Initiative Network?
Not yet. If S-40 is your boat, you can claim it free and join the Master's Mate Safety Initiative Network (MMSIn).
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