Sailing the wrong course

If a boat fails to sail the right course (misses passing through start/finish line in this case) and this only noted by the RO, not the helm or other competitors what happens next?

I don't think the RO can summarily DSQ the competitor or in handicap racing not record a lap time (?)

Is it more that the RO has to have a word with the helm indicating what they did and inviting them to retire otherwise the only resolution could be a protest instigated by the RO?

On whom is the onus of proof?

At our club if this happens they are put on the result sheet as DNF as they are deemed to have retired. The RO will not record a time on the results sheet.

Surely it does not matter whether it is class or handicap racing?

Something like this situation happened at the Formula 1 nationals this year. 

At the end of the last race on the first day a boat rounded the leeward mark in about 5th place and sailed towards the finish line, but did not cross it.  Instead (presumably thinking it had finished) the boat turned away (downwind) just before the finish line and went back to its moorings. 

This was seen by the RO and witnessed by two assistants on the committee boat (I was one), which was stationed at the end of the finish line.  The RO recorded the boat as DNF, but only after waiting for ~half an hour after all the other boats in the race had finished to see if the boat that had turned away would return to complete the course.

The RO and team were essentially stuck out on the pond waiting, with no way of knowing the boat's intentions. 

Eventually, back on shore the crew of the DNF boat were not happy when they learnt of the DNF scoring applied, but what else could the RO do? 

There is no requirement to hoot when each boat finishes, and all of the other boats in the race managed to cross the line,

Edited by asterix

I thought the rule was thirty mins after the first boat is the time limit so if that boat had not crossed the line in that time he would be DNF

A Race Committee may only determine a boat's score as other than their finishing place for boats that do not start or do not finish, retire after finish or take a scoring penalty after the finish. Only the protest committee may take other scoring actions that worsen a boats score (see rule A5)

A boat that sails through the start/finish line on a lap of the course is neither starting nor finishing. If the course requires boat to sail through the line on a lap of the course and they fail to do so, Race Committee MUST, repeat MUST, protest under rule 28.1 in order to get boat disqualified. If the disqualify boat without a hearing then boat can request redress, which should be granted. By this time any subsequent Race Committee protest would almost certainly be too late.

Unfortunately, once first boat finishes Race Committee must keep line open until time limit expires or all boats have finished or retired. 30 minutes may be too ong a time limit for one fleet races which do not last too long.

Gordo