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.
Tug
KAISEI MARU
MMSI 431020655 · Call sign JD5201
Not yet on Master's MateType
Tug
Flag
JPNLength
32 m
Beam
11 m
Draft
4.4 m
Call sign
JD5201
First reported
Jun 2026
Last reported
Jun 2026
AIS reports
25
KAISEI MARU is a harbour tug hailing from Japan, 32 metres long. Below, she has a 11-metre beam and a draft of 4.4 m. On the registers she's MMSI 431020655, call sign JD5201. Put KAISEI MARU on the Master's Mate Safety Initiative Network — free to claim, with a whole fleet watching out for her.
Free forever · No credit card · for working boats
Built for boats that work — like KAISEI MARU.
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
Last known position · Jun 3, 2026
Position
37.8355° N, 140.9596° E
Working the Sea of Japan? You're never out there alone.
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The most powerful cruising platform ever built — yours, free.
Joining the Safety Initiative Network doesn't just put KAISEI MARU 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 KAISEI MARU and switch it all on
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About KAISEI MARU
What kind of vessel is KAISEI MARU?
KAISEI MARU is a Tug flagged to Japan.
Where was KAISEI MARU last seen?
KAISEI MARU was last reported in the Sea of Japan in Jun 2026 on public AIS.
What is KAISEI MARU's MMSI?
KAISEI MARU's MMSI is 431020655. Call sign JD5201.
How big is KAISEI MARU?
KAISEI MARU is about 32 m long, 11 m on the beam, drawing 4.4 m.
Is KAISEI MARU on the Master's Mate Safety Initiative Network?
Not yet. If KAISEI MARU is your boat, you can claim it free and join the Master's Mate Safety Initiative Network (MMSIn).
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