Downwind Rhumb line or Reach Off

[Bob Kirsten]

Gang,
Question on downwind sailing angles, and I would like to ask if from two different points of view.
1. Racing JAM - We have a fair bit of light air on Lake Saint Clair, and have joined in the PRF club racing, not one design. Last race had a dead downwind run to the mark, and most of the other JAM's went wing and wing. We reached off about 30 degrees, then jibed back and did not appear to gain anything (board 1/2 way up). We then set her wing and wing (poled out) and appeared to do well, even though the bigger masthead rigs could put a shadow down on us. Board was all the way up. What is your recommendation - To REACH OFF or TO RUN DEAD DOWNWIND??????

2. Racing spinnaker - Same question - What is your recommendation - To REACH OFF or TO RUN DEAD DOWNWIND??????

[BarryE]

Depends on conditionds, 9 times out of 10, on a short windward/leeward course I'd say go direct, to the mark, shortest distance. Reaching out will work, but only in the lightest of air when you can't get any movement dead down. If your chute/genny collapses as soon as you get some boat speed, then maybe its time to break off some.

[Bob Kirsten]

Thanks for the reply, makes sense. The AB course on Lake St Clair runs about 2 miles per leg, so it leaves room for thinking (probably too much).

R Kirsten

[Fred Chadsey]

Look at polars for downwind sailing, which relates to angle relative to wind speed. Under chute we take board up to 1/4 and sail down rumline. In light air 3-4kts go w/ genoa wing/wing w/ board up is faster, again rumline.

[Bob Kirsten]

Fred, Thanks for the comments. You are right, I should look at the polar.

Bob Kirsten
DD Mau
438