RRS D5.2 states …
When a boat suffers a breakdown in the racing area, she may request a score change by displaying a red flag at the first reasonable opportunity after the breakdown until it is acknowledged by the race committee or by an umpire. If possible, she shall continue racing.
What is the “racing area” in this circumstance? If the jib halyard breaks on an OA-supplied-boat on the way out from the dock before the first race, should a boat continue out to the starting area under main-alone, follow D5.2 and try to sail near an umpire? … or turn back to the dock and file a request for redress ashore?
You get the favorite Umpire response of "it depends"
Is there someone on the dock who could fix it? ie do you have a breakdown officer?
Is this the type of boat where the jib tension could be considered critical? (rolling the boat and tying the jib up the mast might get you racing but , , ,)
Is the forestay going to hold the mast up while you wind on the mainsheet tension if you race?
Does the boat need fixing for other races?
How far out were you when it broke and how far is it back to the dock?
With our short distances going back ashore and getting it fixed or getting a spare boat is probably best.
Just remember to display your red flag and have it acknowledged - it's amazing how many don't!