October 2017 - What to watch for when you are going leeward

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October 2017 - What to watch for when you are going leeward

Last month, I looked at two boats going downwind towards the leeward mark. This month, we will discuss the interaction between upwind and downwind boats.

In the diagram, we start with two boats, White and Blue, sailing downwind. Blue is on starboard tack while White is on port tack. They are paying attention to each other and not looking to their respective leeward sides, where two other boats are approaching, sailing upwind. Green is on starboard tack and Red is on port tack.
First, we will look at Blue and Green. Both boats are on starboard tack. It may not be obvious at first, but until they pass each other, Green is to leeward of Blue. The definition of windward and leeward says “When two boats on the same tack overlap, the one on the leeward side of the other is the leeward boat. The other is the windward boat.” If we look at the expansion of the boats at position 3, we can see that Green is on Blue’s leeward side. This makes Green the leeward boat and Blue the windward boat. Rule 11 says that Blue must keep clear of Green. If Blue had noticed Green earlier, it is possible that there is another way around. As it is, when Blue notices, the only way to keep clear is to gybe.

A very similar situation exists between Red and White. Red is the leeward boat but here, White is just a bit further ahead and is able to cross Red. At position 4, Red is now to windward of White. There is a transition where Red goes from being leeward boat and right-of-way to being windward boat and give way. It is not clear exactly where that position is – but there is some elasticity in the rules. At the time the transition happens, White is subject to rule 15. Rule 15 requires her initially to give Red room to keep clear. By that time that “initially” has passed, the boats have passed as well.
It is simplest to think that whenever it matters, the boat going to windward has right-of-way over the boat on the same tack going to leeward. That is not actually the rule but it is a simple summary of the effect of the rule. I carefully said that this applies to boats on the same tack. Boats on starboard tack, even those going downwind, have right-of-way over boats on port tack, even those going upwind.
When you are going downwind, please remember – watch out for the boats coming upwind. If you are on starboard tack going downwind, like Blue before her gybe – watch out for starboard tack boats going upwind. If you are on port tack, like White, watch out for upwind boats on both tacks. A timely gybe or a slight luff to pass ahead is much faster and safer than a last-minute panic.
As an historical side note, this rule reverses what our predecessors knew. At one point, boats with spinnakers up had right of way over boats going upwind. I think that had all disappeared before the Second World War so we really shouldn’t be confused today.

Leeward and Windward A boat’s leeward side is the side that is or, when she is head to wind, was away from the wind. However, when sailing by the lee or directly downwind, her leeward side is the side on which her mainsail lies. The other side is her windward side. When two boats on the same tack overlap, the one on the leeward side of the other is the leeward boat. The other is the windward boat.
When boats are on the same tack and overlapped, a windward boat shall keep clear of a leeward boat.
When a boat acquires right of way, she shall
initially give the other boat room to keep clear,
unless she acquires right of way because of the
other boat’s actions.


© Copyright 2017 Andrew Alberti
Posted: 4/29/2019 11:10:41 AM by Andrew Alberti | with 0 comments

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This page provides links to a set of articles original published in Kwasind magazine. The versions here include animated diagrams. The original articles can be found within the original magazines which are available online back to January 2007. 

Articles before December 2020 are based on the Racing Rules of Sailing 2009-12 or 2013-2016 or 2017-2020 and have not been updated to reflect the changes that apply as of January 2021 with the publication of the Racing Rules of Sailing 2021-24. A copy of the new rules can be found on sailing.org.
Andrew Alberti has been writing these monthly articles in the Kwasind since early 1997.  They explain the Racing Rules of Sailing. Andrew is an International Judge and National Umpire. He is a member of the Sail Canada Rules and Appeals Committees. The interpretation of the rules contained in the articles is Andrew's and not that of the RCYC or any of the committees he sits on. 

Send your questions to Andrew at kyrules@alberti.ca.


166 Years of Tradition | World-Class Sailing | Toronto Island & City Clubhouse
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