Needed to compute apparent wind (AWA) on the WIND tile - always knots here regardless of the display unit below. "Fetch forecast wind" fills this in too, or set it by hand.

Auto-detected once you've sailed both tacks. Typing a value here locks it - auto-wind stops overwriting it until you toggle auto-wind off then on, or run calibration again.

Which readouts and overlays the WIND tile shows.

The tack angle guides mark the close-hauled headings either side of true wind, using the tack angle above - they need a tack angle set (calibrate or type one in) before they'll draw.

Once you've been sailing upwind on both tacks, wind direction keeps correcting itself from your average heading on each tack over a rolling window - no need to recalibrate every shift. You'll also get a HEADER/LIFT alert on the Instruments page when it moves.

Level the boat as you want it to read zero, then zero each axis below. The mount is never perfectly plumb.

If GPS errors out (lost signal, permission issue), the app automatically retries after this delay rather than needing a page reload.

Which raw accelerometer axis reads as heel - depends on how the phone is mounted. Recommended: tap Calibrate and rock the phone the way HEEL should actually move - whichever axis swings the most becomes the HEEL axis. Heel and trim can't share an axis; calibrating (or manually picking below) one already used by trim swaps trim to the other. Zero HEEL (above) corrects for a mount that isn't perfectly plumb and isn't affected by (re-)calibrating.

Or pick the axis manually (approximate mounts, confirm on the water): upright in a bracket, portrait - usually X. Upright in a bracket, landscape - usually Y. Mounted flat (screen up) or screen-out against a mast/bulkhead - usually Z.

If HEEL reads backwards - port shows as starboard or vice versa - flip this instead of remounting the phone. Independent of TRIM's own invert below.

Which raw axis reads as trim (fore-aft tilt) - independent of heel's own axis choice above. Recommended: tap Calibrate and rock the phone bow-down/bow-up, the way TRIM should actually move.

Or pick the axis manually - same mount examples as heel, just the other bracket axis: portrait - usually Y. Landscape - usually X. Flat or screen-out mount - usually Z.

If TRIM reads backwards - bow-down shows as bow-up or vice versa - flip this instead of remounting the phone. Independent of HEEL's own invert above.

How often the COG, HEEL and TRIM readouts refresh. Slower rates average the samples received in between rather than just sampling less often, so they read smoother, not laggier.

Fuses the phone's compass into the COG display at low speed (e.g. pre-start maneuvering), where GPS heading gets noisy. GPS course-over-ground stays the source of truth for tacking/wind detection and GPX export at real sailing speed - this only touches the COG readout and map rotation.

Switch to icons if your phone's text scaling squeezes the labels.

By default the Route map rotates to heading-up, like a chartplotter. Lock it to north-up instead if you'd rather the map never rotates.

Resets wind/tack/unit/theme settings, the start sequence and the Instruments tile layout back to defaults. Does not delete recorded sessions.