Helmwright Nautical Calculator

Helmwright is a navigation calculator for sailors, skippers, delivery crews and navigation students. It works like a hardware calculator: a sea-green chassis, real keys and a clear LCD, with each answer labelled so you know what you are reading. SPEED, TIME AND DISTANCE • Any two of speed, time and distance give the third, in knots and nautical miles • ETA from a departure time • Hull speed and speed-length ratio from waterline length CURRENT • Course to steer and speed made good against a known set and drift • Course and speed made good from course, speed and current • Set and drift from your dead-reckoning position and a fix COMPASS • True to compass and back: variation and deviation, east or west HORIZON AND LIGHTS • Distance to the horizon from height of eye • Geographic range of a light • Distance off by vertical sextant angle TIDES AND FUEL • Height of tide by the rule of twelfths, for any range and duration • Endurance, range and fuel for a trip from burn rate WORKS THE WAY YOU DO • Feet or metres for heights, gallons or litres for fuel • A results strip shows every solved value at once • 10 memories, a tape of your calculations, reference tables and a key guide FREE TO TRY, THEN UNLOCK ONCE Free to try: every feature for 7 days. Then unlock Pro once — no subscription, no ads, works offline. PRIVATE BY DESIGN Works offline, no account, no data collected. How it's calculated: the formulas and tables behind every result, at https://wrightcalc.app/helmwright/ Questions or feedback: support@wrightcalc.app For passage planning and training. Not a substitute for official charts, tide tables, notices to mariners or proper watchkeeping. Verify every result. The developer accepts no liability for loss or damage arising from use.