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.

Recreational

Slide Rule

MMSI 366893780 · Call sign WDH4007

Not yet on Master's Mate

Type

Recreational

Flag

USA

Length

11.9 m

Beam

3.7 m

Draft

1.6 m

Call sign

WDH4007

Official No.

1078502

AIS reports

An American leisure boat, Slide Rule measures 11.9 metres. She's built with a beam measuring 3.7 metres and a 1.6-metre draft. On AIS she appears as MMSI 366893780, call sign WDH4007. Slide Rule is exactly the kind of boat the Master's Mate Safety Initiative Network was built for — free, simple, and always on watch.

Free forever · No credit card · for recreational captains

Keep Slide Rule looked after — even when you’re not aboard.

Anchor alarms that wake you, a live camera at the dock, and weather you can trust before every run.

Look after her — claim free →

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

Wherever Slide Rule 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 recreational captains

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

Joining the Safety Initiative Network doesn't just put Slide Rule 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.

Onboard Cameras

Watch your boat from anywhere — live feeds and 24h recording, straight from your gateway.

Weather & Routing

GRIB wind, swell & current on the chart. Plan passages with ETA-calibrated forecasts per leg.

Worldwide Charts

Navionics-grade vector charts, satellite & raster overlays, online or off. Your whole cruising ground.

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.

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 Slide Rule and switch it all on

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

Claim free → unlock everything

About Slide Rule

What kind of vessel is Slide Rule?

Slide Rule is a Recreational flagged to United States of America.

What is Slide Rule's MMSI?

Slide Rule's MMSI is 366893780. Call sign WDH4007.

How big is Slide Rule?

Slide Rule is about 11.9 m long, 3.7 m on the beam, drawing 1.6 m.

Is Slide Rule on the Master's Mate Safety Initiative Network?

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