Q.What is the difference between a narrow channel and a fairway according to COLREGS ?

The FAIRWAY is considered to be the deep water channel which may be marked by broken lines on the chart for use by large vessels whereas the term NARROW CHANNEL refer to whole width of navigable water b/w the lines of the bouys.

The channel is the natural or dredgred lane restricted on either side by shallow water,its is often marked by buoys. A fairway is in open water,and the water on eitherside is not much shallow than within fairway. Fairway are general used to enroute the vessel away from natural hazards, oil platforms, mines.