Race Passing on Reach to Windward


  I am sure someone a lot smarter than me has solved this before.  We race at our tiny lake at The Asheville Sailing Club.  Usually 15 boats, 5 of which are FS.   Our starts always start at our narrow cove and we take off on a reach to the first mark.  So there are no standard tacks, just sail fast.  So, I often end up between a few FS on similar courses.  Yesterday I was getting some progress on a boat to leeward and pulled to pass him upwind on windward. Both boats on starboard tack.  He slightly moved upwind.  I responded by pulling my boom in.  At the critical moment our boats were about 6' apart, both still charging ahead on reach.  Wind at a steady 10 knots.   As my wind shadow caught him, his boom came across his boat onto a Port tack  and his sail filled fully, with his jib across to the Port side, but held by his jib sheet.   The end of his boom landed atop the end of my boom.  I was still on solid starboard.  No boat damage.  We just lifted his boom off ours and he fell off downwind a bit.  I called protest, saying he had come over on port and collided with my boom.  Everyone agrees that the rules say that the windward boat has to keep clear.  But just how is this done?   This is a very common situation as almost all our races are on reach.  Is it common for a boat being passed to appear to be on Port tack all the sudden?  Was this caused by the wind shadow, or was this one of our fluky bizzarre puffs....   If so, surely this has been addressed many times before.  I'd love to hear some comments, not so much for my silly sailing, but to instruct our fleet, as this is coming up in various fashions from time to time.

Yes, it sounds like if you were still traveling roughly parallel, on a reach, that you would both still be on starboard.  If you are windward you need to keep clear and six feet is close.  Your boom is 11 feet long, and if they come up under you and touch your boom, then you have not kept clear.
The game changes as you approach a mark or obstruction.  It would also change if the wind shifted and you were basically running, where two boats on nearly parallel courses can be on opposite tacks and converging.

James Titus's picture

My boom at the time was strapped in almost to my center, as I did not want to get near his shroud.  His boom was way off to starboard on the reach.  He was not altering course to come upwind on me.   The question I still have is did my wind shadow create some kind of vortex, vacuum, that created his own personal wind that blew his main and jib across his boat?  This is what happened.  If it was some kind of wind shift, it would seem that my main and jib would have felt something, but that didn't happen.
My weak point is that my boom was strapped in, and it was his boom that came way over and came aboard my boat to hit my boom, while my hull was 6' away.   I know there is no exonoration under the rules, but I am trying to understand the physics of it.   Do you think it is more likely an odd wind shift, or some aspect of wind shadow?