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.
Towing Vessel
PB4
U.S. Official No. 1321778
Not yet on Master's MateType
Towing Vessel
Flag
USALength
7.7 m
Beam
4.3 m
Draft
1.8 m
First reported
Jun 2026
AIS reports
1
PB4 is a work boat wearing American colours, spanning 7.7 metres. She has a beam of 4.3 m and a draft measuring 1.8 metres. Find her under U.S. official number 1321778. Join PB4 to the Master's Mate Safety Initiative Network — free, and built by cruisers for cruisers.
Free forever · No credit card · for working boats
Built for boats that work — like PB4.
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 PB4 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 PB4 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 PB4 and switch it all on
Free to join · nothing to install to start · cancel anytime
About PB4
What kind of vessel is PB4?
PB4 is a Towing Vessel flagged to United States of America.
What is PB4's U.S. Official No.?
PB4's U.S. Official No. is 1321778.
How big is PB4?
PB4 is about 7.7 m long, 4.3 m on the beam, drawing 1.8 m.
Is PB4 on the Master's Mate Safety Initiative Network?
Not yet. If PB4 is your boat, you can claim it free and join the Master's Mate Safety Initiative Network (MMSIn).
© 2026 Master’s Mate. All rights reserved.