Sail Skills - ColRegs Free Guide to ColRegs (the International Regulations for Preventing Collisions at Sea, the IRPCS or Collision Regs).  Guidance covers all aspects with animations, pictures and diagrams.  Aimed at small vessel users but suitable for professional mariners.  Especially recommended for RYA examination candidates.
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ColRegs Home>ColRegs>Signals>Manoeuvring & Warn>Alter and Astern These signals may be supplemented by a light signal comprising the same number of flashes.  This light signal may be repeated throughout the manoeuvre A power-driven vessel underway in sight of another indicating she is altering course to starboard This shows the usual way to avoid collision in these circumstances - alter to starboard and pass astern of the crossing vessel ...   although in reality a greater separation should be allowed  Altering to starboard is not possible in the animations below: A power-driven vessel underway in sight of another indicating she is altering course to port A power-driven vessel underway in sight of another indicating she is operating astern propulsion Note that the last animation demonstrates that engines must also be used if necessary to avoid collision Many power-driven vessels, especially larger ones, will use the sound signals above whenever other vessels are sight  This is often considered to be a useful safety measure back to top Diagram of a vessel approaching a bend where the view is obscured Diagram of vessels manoeuvring in sight of each other Diagram of one vessel overtaking another A Royal Navy warship with a small motor boat closing - risk of collision exists Power-driven altering course and astern Concern at another vessel Overtaking in narrow channel or fairway View obscured in narrow channel or fairway
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Alter to stbd.mp3 Alter to Port MP3.mp3 Operating Astern Propulsion MP3.mp3