Hull Speed vs SailNav GPS

Hull Speed is a simple speedometer for sailors. It shows your speed over the water in knots — big, clear, and accurate — on your iPhone and Apple Watch, with nothing else to clutter the display. Built for trimming sails: make a small adjustment, then watch the live trend graph to see if the speed changed. FEATURES • Accurate GPS speed in knots, updated every second, using the same Doppler method as dedicated marine instruments — no paddlewheel to foul or calibrate. • A live speed graph on a steady, fixed scale, so a small gain from a trim change is easy to spot. • Enter your boat's waterline length and Hull Speed draws your theoretical hull speed right on the graph — see at a glance how close you are to it. • Apple Watch app with a Keep Awake mode that holds the screen on while you sail. • Completely private — your location is used only to compute speed on your device, and is never stored, sent, or shared. No accounts, no ads, no tracking.

SailNav GPS is your essential sailing companion, designed exclusively for Apple Watch. GPS-only — no internet connection required, so it works wherever you sail. DASHBOARD All your essential sailing data at a glance: speed over ground, course over ground, heading, and your exact position. NAVIGATION Navigate to a waypoint or follow a route with ease. Clear heading guidance, distance to go, and estimated time of arrival — always visible. ANCHOR ALARM Drop anchor and get alerted if you drift out of range. Customize your radius, alarm delay, and alerts, and watch your live position relative to the anchor. MAN OVERBOARD (MOB) Mark a man overboard position instantly with a long press from anywhere in the app, and get clear direction and distance back to them, fast. TRIP RECORDING Track time, distance, average speed, and maximum speed during your trip. SETTINGS Choose your appearance, coordinate format, and distance and speed units to match how you sail. Built by sailors, for sailors. Focus on what matters on the water. Tip: for the best experience while sailing, set Return to Clock to "After 1 Hour" in your Watch settings (Apple Watch → Settings → General → Return to Clock), so SailNav GPS stays easily accessible when you raise your wrist underway.