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.

Tanker

RYOSEI MARU

MMSI 431301018 · Call sign JL6618

Not yet on Master's Mate

Type

Tanker

Flag

JPN

Length

71 m

Beam

11 m

Draft

3.7 m

Call sign

JL6618

IMO

8944173

First reported

Jun 2026

Last reported

Jun 2026

AIS reports

On the Japanese registry, RYOSEI MARU is a 71-metre tank vessel. Below, she has a 11 m beam and a draft of 3.7 m. Her registration reads MMSI 431301018, call sign JL6618, IMO 8944173. RYOSEI MARU can join the Master's Mate Safety Initiative Network for free: think of it as a watch network that has every boat's back.

Free forever · No credit card · for commercial operators

Eyes on RYOSEI MARU, 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

Last known position · Jun 3, 2026

Track RYOSEI MARU live — sign up free →

Position

38.3191° N, 141.0374° E

Transiting the Sea of Japan? 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 RYOSEI MARU 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 RYOSEI MARU and switch it all on

Free to join · nothing to install to start · cancel anytime

Claim free → unlock everything

About RYOSEI MARU

What kind of vessel is RYOSEI MARU?

RYOSEI MARU is a Tanker flagged to Japan.

Where was RYOSEI MARU last seen?

RYOSEI MARU was last reported in the Sea of Japan in Jun 2026 on public AIS.

What is RYOSEI MARU's MMSI?

RYOSEI MARU's MMSI is 431301018. Call sign JL6618. IMO 8944173.

How big is RYOSEI MARU?

RYOSEI MARU is about 71 m long, 11 m on the beam, drawing 3.7 m.

Is RYOSEI MARU on the Master's Mate Safety Initiative Network?

Not yet. If RYOSEI MARU is your boat, you can claim it free and join the Master's Mate Safety Initiative Network (MMSIn).