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

JOHNA B.

U.S. Official No. 505387

Not yet on Master's Mate

Type

Tank Barge

Flag

USA

Length

73.2 m

Beam

15.3 m

Draft

3.2 m

First reported

Jun 2026

AIS reports

Registered in the United States, JOHNA B. is a 73.2-metre tank ship. She carries a beam of 15.3 m and a 3.2-metre draft. She's on record as U.S. official number 505387. Join JOHNA B. to the Master's Mate Safety Initiative Network — free, and built by cruisers for cruisers.

Free forever · No credit card · for commercial operators

Eyes on JOHNA B., 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 JOHNA B. 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 JOHNA B. 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 JOHNA B. and switch it all on

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

Claim free → unlock everything

About JOHNA B.

What kind of vessel is JOHNA B.?

JOHNA B. is a Tank Barge flagged to United States of America.

What is JOHNA B.'s U.S. Official No.?

JOHNA B.'s U.S. Official No. is 505387.

How big is JOHNA B.?

JOHNA B. is about 73.2 m long, 15.3 m on the beam, drawing 3.2 m.

Is JOHNA B. on the Master's Mate Safety Initiative Network?

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