Oct 19, 2020

RULES STUDY


Room at leeward mark

This discussion touches on rules involving proper course (you can sail above your proper course if you achieved an overlap from more than 2 boat lengths away from the boat being overtaken, otherwise you cannot sail above proper course), windward leeward (windward boat keeps clear of leeward boat) and bouy room within the zone (the zone comes into play 4 boat lengths from the bouy).

 

The Luffing vs Mark-Room at a Leeward Mark


This month I will discuss two sets of actions – frequently seen when boats approach a leeward mark – and their consequences. In the diagram, Blue and Red are both sailing downwind on port. The diagram shows them with spinnakers, but the issues are the same in a whitesail race.

leeward mark room

Red is sailing directly downwind; Blue is reaching a little more. The boats are overlapped and since Blue is leeward boat, Red must keep clear of Blue to comply with rule 11. We don’t know how the overlap was established, but if it was established by Blue from clear astern within two boatlengths of Red, rule 17 would then have applied. However, it doesn’t apply anymore, since at position 1, the boats are more than two boatlengths apart. Accordingly, since Rule 17 either never applied or no longer applies, Blue is allowed to sail above her proper course. They are not yet in the zone, so mark-room does not apply.

 

From here, two possibilities play out. Blue has the right to luff Red up, thereby taking her away from the zone. At position 5, the boats get close but Red does not respond, so by position 6, Blue is forced to alter course to leeward to avoid a collision. Red has broken rule 11 and Blue protests.

 

A second possibility – Red mobilizes one of two possible defences. The simplest is to get to the zone before Blue approaches. As soon as one of the boats touches the zone – which Red does just before position 7 – rule 18.2 starts to apply. Since Red is entitled to mark-room according to rule 18.2(b), Blue must now adjust her course to allow Red “to sail to the mark” (directly).

 

Many make a mark-room call far too early. If you know your speed, it isn’t too hard. One knot is about 1.7 feet per second. A 35-foot boat travelling at 5 knots takes a bit more than 4 seconds to travel 1 boatlength. So 12.5 seconds should elapse between an accurate call for room and the bow being level with the mark. If, on the other hand, it takes 30 seconds, your call came more than 7 boatlengths out – 4 boatlengths early. In the same 30-second interval, an Optimist travelling at 4 knots would have gone 25 boatlengths – a bit too generous.

Red’s second possible defence is to gybe onto starboard near position 2 – a simple option since she is sailing directly downwind. Once Red is on starboard, Blue – on port, remember – has to keep clear. Either way, Red is in the clear.

 

The things to remember are, if you are Blue, your luffing rights are powerful, but only if you meet the conditions that grant them. If you are Red, your defences are equally powerful, but only if you remain aware of what nearby boats are doing and act in good time.
 



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