Tools for Sailors and Yacht Crews
23 toolsA kit for the watch and the passage: a COLREG lights and shapes trainer, a light characteristic decoder, tide predictions, compass error from the sun, a maneuvering board with CPA and TCPA, rest-hour records, an anchor watch and port-to-port routing.
Sea & navigation
Ship lights under COLREG-72
Vessel lights, day shapes and sound signals under COLREG-72: identify ships from any aspect by night and day, take an exam, see the rule. Online.
Light characteristic
Paste a chart abbreviation — Fl(3)WR.15s12M — and get it decoded, the rhythm played live, and the range of first sighting. Plus IALA buoyage.
Compass error
Compass error from the azimuth of the Sun, Moon and stars, amplitude, a deviation table from A–E coefficients and course conversion. Ship's time.
Marine coordinates
Degrees and minutes, DMS, UTM, MGRS from any entry. Rhumb line and great circle between points, GPX export and a phonetic readout for VHF.
Seafarer hours of work and rest
Seafarer hours of rest record under STCW and MLC: 10 h in any 24 h, 77 h in any 7 days, rolling windows, breaches and a form to sign.
Maneuvering board
Two radar plots give the target's course, speed, CPA and TCPA with an honest error bound. Trial maneuver and exercises with answers.
Anchoring and anchor watch
Rode length from the depth at high water, swinging circle, chain catenary — and a GPS drag alarm that runs in the browser.
Sea distance between ports
A route over water between any two ports: nautical miles, passage time, fuel. Computed in your browser, with canal options and no limits.
Tide Times
High and low water times for any coastal place, a tide curve two weeks ahead and under-keel clearance. Computed in your browser, works offline.
Small-craft skipper practice test
The official EMERCOM question list — 1,221 questions with answers by vessel type and navigation area, plus a ticket in the order No. 90 format.
Space & nature
Sun & Moon
Find sunrise, sunset, golden hour, day length and the moon phase for any location, with live sun and moon directions on a map. Free.
Weather
Hourly and 9-day weather from two independent forecast models at once — with the disagreement between them shown, not hidden.
Wind Map
Watch live animated wind across the globe from the GFS model — wind speed and direction anywhere, with a reading for your own location. Free.
Lightning Map
Live lightning map from satellite data: see where storms are striking now, how far the nearest one is from you and which way it is moving. Online.
Measure on map
Trace a plot on the map and get its area on the WGS84 ellipsoid — in hectares or acres — not the area of the picture on screen.
Measuring
Calls & sharing
Other tools
Morse Code Generator
Convert text to Morse code with audio playback. Adjust speed and tone, download as MP3 or WAV.
Morse Code Decoder
Decode Morse code from audio — record from microphone or upload a file. Real-time analysis to text.
GPX Viewer and Converter
Open GPX, KML, KMZ, FIT or TCX files on a map with an elevation profile and climbs, draw a route, and save it for Garmin, Strava or Google Earth.
Battery Calculator
Runtime, charge from voltage and charging for 12 V, AGM, gel, LiFePO4, Li-ion and LiPo