The angle of repose or, more precisely, the critical angle of repose,[1] of a granular material is the steepest angle of descent or dip of the slope relative to the horizontal plane when material on the slope face is on the verge of sliding. This angle is given by the number (0°–90°).
Rule two comes into picture when there is immediate danger + special circumstance, hence when you see a vessel ahead and you have a vessel at your starboard quarter, both at close ranges, you dont have any option other than to alter course to port widely, henceyou deviate from rules. Hope this helps!
