The Heel page reads heel and trim from the phone's own motion sensors. Mount the phone firmly; anything that lets it move will read as heel.
Set it up
- Mount. In Setup › Heel and trim, choose Upright (on the mast or a bulkhead, screen facing aft) or Flat (screen up, top of the phone toward the bow).
- Zero. At the dock with the boat level, press and hold Zero. Heel and trim now read from that level.
Reading it
- The big number is heel in degrees, and the label names the side: HEEL TO PORT or HEEL TO STBD.
- The five bars beside it are how steady the heel has been over the last ten seconds: five bars under 1° of spread.
- The LED strip shows your heel against the target band chosen in Setup (for example 10–20°).
- TRIM is bow up or bow down.
Damping in Setup smooths the readings over 1, 3 or 6 seconds.
The horizon
With an upright mount and the camera running, the app also looks at the horizon behind the boat. The phone's motion sensors are fooled by long accelerations, a steady turn or a sea lifting the boat; the horizon is not. The app learns the difference slowly and corrects the heel, and the label adds HORIZON while it does. See Race video.