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.

Vessel

HORIZON CHALLENGER

MMSI 366946250 · Call sign EX18

Not yet on Master's Mate

Flag

USA

Call sign

EX18

Official No.

515155

AIS reports

HORIZON CHALLENGER is an American vessel. Find her under MMSI 366946250, call sign EX18. Bring HORIZON CHALLENGER aboard the Master's Mate Safety Initiative Network — free, and every captain on it has the others' backs.

Free forever · No credit card

Is HORIZON CHALLENGER 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 HORIZON CHALLENGER 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 HORIZON CHALLENGER 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 HORIZON CHALLENGER and switch it all on

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

Claim free → unlock everything

About HORIZON CHALLENGER

What kind of vessel is HORIZON CHALLENGER?

HORIZON CHALLENGER is a vessel flagged to United States of America.

What is HORIZON CHALLENGER's MMSI?

HORIZON CHALLENGER's MMSI is 366946250. Call sign EX18.

Is HORIZON CHALLENGER on the Master's Mate Safety Initiative Network?

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