Sign up free Dashboard Log out
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.
Mobile Offshore Drilling Unit

PERCY JOHNS

U.S. Official No. 633949

Not yet on Master's Mate
Type
Mobile Offshore Drilling Unit
Flag
USAUSA
Length
54.9 m
Beam
53.3 m
Draft
7.4 m
First reported
Jun 2026
AIS reports
1

PERCY JOHNS, an American vessel, measures 54.9 metres on deck. She's built with a beam of 53.3 m and a 7.4-metre draft. She's on record as U.S. official number 633949. PERCY JOHNS is invited to the free Master's Mate Safety Initiative Network, where cruisers keep each other safe.

Free forever · No credit card

Is PERCY JOHNS your boat?

Your free claim unlocks the most powerful cruising platform ever built — anchor watch, worldwide charts, live AIS, weather routing, and a network of cruisers watching each other’s backs.

Claim this boat — free →

Takes 60 seconds · Your data stays yours · Built by cruisers, for cruisers

Wherever PERCY JOHNS 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

The most powerful cruising platform ever built — yours, free.

Joining the Safety Initiative Network doesn't just put PERCY JOHNS on the map. It hands you the full bridge:

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.
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.
Onboard Cameras
Watch your boat from anywhere — live feeds and 24h recording, straight from your gateway.
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.
Hail Any Captain
A verified captains directory + direct hailing. Reach the boat next to you, or across the bay.
Claim PERCY JOHNS and switch it all on
Free to join · nothing to install to start · cancel anytime
Claim free → unlock everything

About PERCY JOHNS

What kind of vessel is PERCY JOHNS?
PERCY JOHNS is a Mobile Offshore Drilling Unit flagged to United States of America.
What is PERCY JOHNS's U.S. Official No.?
PERCY JOHNS's U.S. Official No. is 633949.
How big is PERCY JOHNS?
PERCY JOHNS is about 54.9 m long, 53.3 m on the beam, drawing 7.4 m.
Is PERCY JOHNS on the Master's Mate Safety Initiative Network?
Not yet. If PERCY JOHNS 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.