Navigational template and its use for defining safe passage of craft

摘要

A method and constructional template for defining the area in which two waterborne craft (10,11) approaching each other may safely steer to avoid collision makes use of the statutory orientation and masking of the port, starboard and astern facing navigation lights coloured respectively red, green and white.A template with sector markings (14) matching the beam spread of standard navigation lamps is aligned on a marine chart with its principal axis coincident with a line (13) joining the observer (10) to the light (12) of the approaching vessel (11).A sector is thereby defined relative to the colour seen by the observer in which a course may be set guaranteeing safe passage of the two craft.