Navigation

Magnetic variation & deviation“Do I add or subtract variation?”Convert true, magnetic and compass headings along the T-V-M-D-C ladder, with every step and the sign rule that decided it. Advances a charted variation to the year you are plotting in.Speed, time & distance“How long is this leg, and when do I arrive?”Solve any one of the three on the exam's 60D = ST form, with time entered as hours and minutes rather than decimals, plus an ETA from your departure time.Distance to horizon & light ranges“How far can I see, and when will I raise that light?”How far your horizon is from your height of eye, a light's geographic range from two heights, and which of geography or brightness limits the first sighting.Nautical converter“How many mph is a knot?”Knots, nautical miles and fathoms against mph, km/h, statute miles, metres and feet. Type into any field and every other unit updates at once.

Weather

Beaufort wind scale“What force is a gale, and what flag is up?”All thirteen forces with wind band, sea state and probable wave height, mapped to the NWS warning that would be flying — with the Small Craft Advisory trigger set for your own region.

Credentials

USCG license finder“OUPV or Master — which do I need?”Three questions — tonnage, waters, passengers for hire — map to the credential the Coast Guard is likely to require, with the 46 CFR rule behind each branch.Sea time tracker“Do I have enough sea time yet?”Log service days by vessel and water type and see how they credit toward a credential under 46 CFR 10.107, including the recency window. Stays in your browser.