See – https://www.pyra.org.uk/wp-content/uploads/2023/06/PYRA-Red-Book-2024-Amendment-6.pdf

When we set up the race start times for the race on Sunday from Weymouth to Poole (Race No 15) we thought that we would be sailing back after taking part in the Weymouth regatta. That isn’t the case, so the race start on Sunday (July 14th) has been brought forward to 10.00 in order to make best use of the tide.

See 2024 Red Book Amendment 5