Why is this rule modified?
Shortening the race is a regular occurrence during river races conducted by the PMYC. This is due to variable wind conditions and also the requirement to complete racing at fixed times such as sunset.
How is this rule modified?
This rule is modified to remove the requirement to finish at the next mark and instead for the OOD to broadcast to yachts the modified course and also to describe a finish transit line for the purpose of recording the race elapsed time.