Well, it wouldn't have made much difference on any of the finish lines if you and your friends had all gone for the port end. But going for the starboard end -- now that would have been the winning move, gaining you up to 7 boat lengths on line D, and 3 boat lengths on line B. That is more than enough to grab first if you were close astern the leader rounding the leeward mark for the last time, and he went onto starboard immediately. It wouldn't matter for line A, since that finish is exactly perpendicular to the wind.

So, what have we discovered? Other things being equal, and strictly from a sailing or city block distance point of view,

• If the start or finish line is offset to one side or other of the course doesn't one matter one bit (as long as it isn't so far offset that you are suckered into overstanding a layline)
• If you start on starboard tack or on port tack doesn't matter one bit (as long as the wind holds its direction and you make sensible choices of when and where to tack)
• If the wind is not exactly perpendicular to the starting line, you must start at the windward end, period.
• If the wind is not exactly perpendicular to the finishing line, you must finish at the leeward end, period.

But you knew all that, didn't you?

Finally, Larry Robinson has reminded me that other things are not equal on a real course with 18 or so other boats jockeying for position. First, being on starboard tack confers a tactical advantage to a boat, and so a well-set start line is biased with the port end about two boat lengths upwind of the starboard end. (A geometric or Euclidean distance of 2 boat lengths translates into about 3 city block lengths.) This tends to spread the boats along the line by mildly favouring the port end. Second, jockeying for the most favoured position on the line brings risks of contact and risks of being back in the pack in bad air. Maybe you should be towards the favoured end, but keeping clear air and your options open.

There is a little spreadsheet (about 17 kb) that calculates line bias in terms of sailing or city block distances. Have a play.

If the wind bends, the city block metric no longer applies. I've some other diagrams which illustrate some possible courses to steer in this case.

2005-12-18

©2024 Lester Gilbert