Salt and Wire Companion

An onboard app written by marine electrical engineers. Works offline, no account, no ads. Your data stays on the phone.

AN AIS AND VHF RECEIVER FROM AN RTL-SDR DONGLE
An RTL-SDR dongle plugged into the phone turns it into an AIS receiver and a marine VHF scanner. The signal comes off your own antenna and is decoded on the spot rather than pulled from the internet, so it works where there is no coverage. Class A and B vessels appear on the chart with MMSI, name, course and speed, and CPA and TCPA are computed for each: the distance and time of closest approach. The 156-162 MHz band covers channel 16 and the other voice channels, with squelch, a signal meter and a spectrum waterfall. Without a dongle the panel shows a preview of the band, so you can see the interface first.

ANCHOR WATCH
A drag alarm with a radius you set yourself or have the assistant work out: give it the depth, the expected tide rise, the height of the bow roller and the wind force, and you get the recommended scope ratio, the swing circle and a ready alarm radius. Rocks, shallows and neighbours are marked on the chart as circles or polygons. Monitoring keeps running with the screen off and the app minimised, and with the remote alarm switched on the notification also reaches a second phone, ashore for example.

NAVIGATION AND CHART LAYERS
EMODnet bathymetry with isobaths and depth shading, satellite imagery, national topographic maps (German BKG, French IGN, Spanish PNOA) within their coverage and OpenStreetMap beyond it. OpenSeaMap seamarks on top. A route with waypoints gives speed, time to go and the sailed track, and the leg check flags the ones that cross land, pass too close to the shore or clip a charted danger.

OFFLINE MAPS
You mark the areas as rectangles on the chart. The app scales the zoom to the radius - harbour detail close in, passage scale further out - downloads the tiles into the phone, and the navigation module reads them automatically when there is no signal.

LOGBOOK AND DOCUMENTS
Entries on departure, every hour and on arrival: position, course, speed, pressure, sea state. PDF exports cover the logbook, service history, fault report, handover sheet, float plan, charter check-in and check-out, and a sea-time statement.

WEATHER AND SEA STATE
A barometer with 48-hour history, three-hour tendency and a falling-pressure alarm; a phone without a sensor fetches the reading for its position. The sea-state meter works out significant wave height and period from the phone's own motion, the same way a wave buoy does.

CREW MODE
One subscription per boat. The crew installs the free app and sees position, anchor watch, barometer and log, receives the boat's alarms, adds expenses to the kitty and can raise an MOB alert. Access is handed over by touching phones over NFC or with a code.

SYSTEMS AND SERVICING
Service log with photos and voice notes, reminders by date or engine hours, documentation of systems and parts, inventory with a minimum threshold, fuel log with range, seasonal checklists. The diagnostic wizard walks you through multimeter measurements step by step. The calculators size wire from voltage drop and a battery bank from the daily energy budget.

SAFETY
The MOB button stores the position, gives the bearing and distance back, and alerts the crew. The MAYDAY prompter assembles the call with your position read digit by digit. Plus position from bearings without GPS, a COLREG light recognizer, tide tables, watch schedule and safety briefing.

YOUR DATA
Everything on the device, a full backup whenever you ask for one. The sharing features send nothing until you switch them on.

Salt & Wire PLUS (monthly or yearly) unlocks the premium modules: the AIS and VHF receiver, offline maps, remote anchor alarm, position sharing, crew mode, sea-state meter, logbook PDF, boat dossier and charter protocol.

Navigation aid only. It does not replace official charts, a proper lookout or good seamanship.