Kinematic beat — laylines, bias & shift
Port vs starboard beat to a windward mark on a square line — twist the wind or add a timed shift and the symmetry breaks.
Two kinematic boats beat to the same windward mark and tack onto the layline. The line is square and the boats are mirror images, so with steady wind they tie. Now twist it: their headings are stored relative to the wind, so turning the wind knob rotates the whole beat, and adding a Wind shift (drag its amber timeline marker) LIFTS the starboard boat and HEADS the port boat before they tack — so they no longer arrive together. Nothing is re-authored.
Opens the animation on the boat-length grid — scrub it, edit it, or use it as a starting point. Free, no account needed.
How it interacts with other rules
- Rule 10 — On Opposite Tacks · see also
Port keeps clear of starboard on opposite tacks.
- Rule 18 — Mark-Room · see also
Mark-room at the windward mark these boats are laying.