A 3D sim to help you master the two basic rules for avoiding collisions between sailboats Rule A. Approach on different tacks - Port tack shall give way Rule B. Approach on the same tack - Windward shall give way The other boat is obliged to 'stand on', meaning that it should maintain constant course and speed as far as possible. This more specific terminology generally supplants 'right of way' in boating colregs. -- NB In regatta competitions (i.e. fleet- and match racing) these correspond to ISAF rules 10 and 11