Rule 18 before the start

Before the start boats have no proper course and so they can pass the committee boat and pin on any side they wish. So before boats are approaching the line to start (ie before Rule 18 switches off) does anyone know how rule 18 can be applied since the beginning of rule 18 states that it applies between boats that are required to leave a mark on the same side. Or does rule 18 only come into effect after the start, in which case why does the preamble to section C state that rule 18 switches off when boats are approaching the line to start?

Originally posted by Wolf1 Before the start boats have no proper course A boat has no proper course before her starting signal (Definitions:  Proper Course)  and so they can pass the committee boat and pin on any side they wish. But that's not the reason why boats can pass starting marks on any side until they are approaching them to start. The reason is that until they are approaching the starting marks to start, the starting marks do not begin, bound or end a leg on which they are sailing (rule 28.1) and therefore they are not required to leave them on any particular side. So before boats are approaching the line to start (ie before Rule 18 switches off) does anyone know how rule 18 can be applied since the beginning of rule 18 states that it applies between boats that are required to leave a mark on the same side. Rule 18 does not 'switch off' any time before the starting signal (assuming starting marks surrounded by navigable water), because it does not apply: boats are NOT required to leave starting marks in either side until they are approaching them to start (see above);  and when boats are approaching a starting mark to start, no rules of Section C (including rules 18 and 19) apply (Preamble Section C)  Or does rule 18 only come into effect after the start, Yes, except when a starting mark is NOT surrounded by navigable water.  in which case why does the preamble to section C state that rule 18 switches off when boats are approaching the line to start? To prevent barging.  The provision used to be called the 'anti barging rule'.

Rule 18 never comes into force before the start, however if the boats are passing the committee boat and are not about to start, it is not classed as a starting mark at that point and R19 (room to pass an obstruction) does apply.