It’s Rule 18

And it’s completely re-written
So they changed Rule 18 for 2009-2012. In the past, Rule 18 applied to rounding marks and passing obstructions. That was a bit confusing, so they broke the old Rule 18 into two different Rules. Rule 18 now applies to rounding marks while Rule 19 applies to passing an obstruction. The old Rule 18 stuff was a bit too complicated when you are approaching shallow water, so this is a good solution. After all, when did you last call, “I’m going to run aground in two boat-lengths. I need room”?

However, there is still a lot happening at the marks. All the stuff in the old Rule 18 still needs to be there, so this is helpful to break up the Rules. There is one Rule for rounding marks – Rule 18; another simpler Rule for room to pass an obstruction – Rule 19; and a third Rule for room to tack at an obstruction -Rule 20. Together they make up Section C of Part 2 (when boats meet).

But let’s concentrate on the new Rule 18.


I’m in the Zone!
The biggest change you will notice is that many classes felt that two boat-lengths to a mark did not allow enough time for action. Faster moving boats would get to the two boat-length “zone” around a mark and then have almost no time to establish rights and get around the mark. Three was better for most boats and even four for really fast boats like catamarans. Unfortunately, the rules did not allow this to change.

In comes the new Rule 18. No longer is there a specific radius in the Rule. Now Rule 18 simply refers to the “Zone” around the mark and leaves defining the Zone to the definitions. In the definitions, Zone is defined as “area around a mark within a distance of three hull lengths of the boat nearer to it”. So, three it is.

The advantage of this is that the Sailing Instructions can change the definition of “Zone”, if the fleet thinks that a different length would work better. Rule 18 stays the same all the time, but fleets can define “Zone” as appropriate. Most fleets will stay with the RRS and use three lengths, but some will change to meet the fleet’s interests. Unless a change is stated in the SI, the length is three boat-lengths of the boat nearer to the mark.


And I want mark-room
Yes, well, because definitions are making things a bit easier for Zone, you can expect that definitions are getting more complicated elsewhere. In the old rules, you called for “room” if you had the inside at a mark. Now there are two definitions:

Room – the space a boat needs in the existing conditions while maneuvering pomptly in a seamanlike way.
Mark-Room – Room for a boat to sail to the mark and then room to sail her proper course while at the mark. However, mark-room does not include room to tack unless the boat is overlapped to windward and on the inside of the boat required to give mark-room.

Now that is many words to say that, when approaching a mark, you want mark-room. The new definition of “room” is used elsewhere, so Rule 18 is about “mark-room”. Imagine you’re approaching the windward mark on starboard with an overlapped boat to windward of you. When the first of the two boats gets to the Zone, you are going to call, “Mark-Room, please”. Not a big deal, but calling “room” is reserved for other situations.

Next post, we’ll get more into the actual meat of Rule 18, but these definition changes are the biggest change you will notice on the racecourse.

Marshall