Offwind · Sail scan beta
See how your sail shape changes.
Measure rig and mainsail shape from a photo or video frame, then compare boats, trim settings and sessions.
Sail scan is in beta preparation. The scanner is not open yet. Email us to request access and tell us your boat class and what you would like to compare.
Email for beta accessgraham@eger.dev · Requests do not automatically enable access. No purchase is required to ask.
What the beta measures
Place points on the mast and mainsail to measure heel, mast fall-off, side bend, leech shape, clew position and draft-stripe camber. Compare readings from several frames side by side.
Assisted point placement and coaching notes are planned beta options. You review the points against the original picture before relying on a reading.
Photo and measurement guide
- Film or photograph from astern with the masthead, mast at deck and mainsail visible. Keep the camera position consistent between comparisons.
- Include a clear horizon when possible. Choose a sharp frame without a wave or another boat obscuring the rig.
- When access opens, load the photo or choose a video frame. Mark the horizon, mast, sail head, clew and leech; add visible draft stripes for camber readings.
- Check each point, then compare frames taken with similar headings, camera angles and sailing conditions. Record the trim change alongside the measurement.
Reading the numbers
Heel uses the horizon as a reference. Mast fall-off and side bend describe the mast’s position and curve in the image. Leech readings compare the sail’s curve at several heights; draft-stripe camber describes the visible stripe’s depth.
These are measurements of a two-dimensional image. Perspective, camera roll, waves and hidden points affect the result. Compare consistent views; a photo cannot reconstruct the full three-dimensional sail or establish a universal best trim.
Join the beta
Include your boat class, whether you use photos or video, and the trim question you want to answer. Please send only images you have permission to share.
Request access by email →Beta availability and access terms will be confirmed by email. An Offwind subscription does not currently unlock sail scanning.