# Mainsail Controls for conditions



## mikehoyt (Nov 27, 2000)

My boat is a 26 foot fractional rig and has the usual mainsail controls (traveller, sheet, outhaul, vang, backstay, cunningham, halyard).

I am looking for "Sailing For Dummies" for upwind performance. Particularly in lighter airs.

Currently when the wind is light I go for power by easing the main halyard to put a bag in the sail, easing the outhaul by about 2 inches and letting the backstay adjutment off most of the way. As the wind picks up and I feel the boat becoming overpowered I tension the outhaul, main halyard and backstay to flatten the sail. As the wind picks up more I lower the traveller and use the sheet to spill the wind out of the main ... driving with mostly the jib. I mostly ignore the vang and leave it reasonably tight.

So ... I think it''s time to start trimming more wisely. From what I have read it is good to get power out of the main by making it full as you accellerate out of the tack. ... but I am now readinging that in light winds the sail should be flat? after the accelleration? I had been leaving the main full in these conditions.

My biggest problem I have with the reading I have come accross is that it is typically information overload. I am thinking a simple 1-2-3 approach for upwind performance would be nice.

Any comments?

Many Thanks

Mike


----------



## bob_walden (May 1, 2003)

It seems to me you''re past the "sailing for dummies" point, Mike. 

A book I can recommend, which I have yet to get everything out of after over a year of reading and re-reading and re-reading: "A Manual of Sail Trim", by Stuart H. Walker. Something to read, think about, sail, then re-read and so on several times. He organizes the book nicely, focusing on situations: acceleration, low leeway, pointing, etc, and special conditions like dirty air, gust control, ligt-moderate-heavy wind, etc. as well as racing maneuvers.

Re your question about "From what I have read it is good to get power out of the main by making it full as you accellerate out of the tack. ... but I am now readinging that in light winds the sail should be flat? after the accelleration?", yes to both. In general, you want a fuller main coming out of a tack, coupled with footing off a bit--ie, sailing a little below close hauled--to speed up. Then, after you''ve recovered your speed after the tack, focus on pointing, which will usually mean hauling the main back in and flattening out. On the boat I race on, we "give up" the fine-tune on the mainsheet during a tack, which is the 20:1 system on our main. That eases the main sheet by maybe 5-10% during the tack. Then we haul that fine-tune back in maybe 30-0 seconds after the tack.

And about flat sails in light airs--if the wind is light, say 3-5 knots, then a very full shape is called for in most rigs to get the most pressure. But in SUPER-light air--beufort 1 stuff--you want to flatten out again because a slack sail will sag and flutter and loose attachment with whatever airflow is there. It''s better in that case to pull most the slack out so that what little airfow you do have, stays attached to the sail. And of course in light conditions, keep control motions smaill and slow to keep things stable. 

bw


----------



## SandyNicholson (Oct 5, 2004)

The Bible for any serious racer is "Sail Power" by Wallace Ross. Nothing else comes close. Flat is fast in light air, but only in flat water. Rig tension is the next threshold for you to understand. Buy sail power-400 pages, tons of pix and line drawings. Don''t loan it to friends though, my copy never came back...


----------



## dpboatnut (Jun 22, 2002)

"Sail Power" was written in 1976, no? How current is it, or can it be? How does it compare to Bethwaite''s "High Performance Sailing"?

Has anybody else read both? I was about to grab a copy of the Ross book on Amazon until I saw the date.

Chad


----------



## paulk (Jun 2, 2000)

All good titles above. For light air in particular, you might want to try moving the traveler to windward, so the boom ends up on the centerline without having to tighten the sheet a lot. This keeps the sail full and helps provide more thrust forward.


----------



## paulk (Jun 2, 2000)

I found Bethwaite difficult to read -- along the lines of Stuart Walker. Lots of theortetical breakdown and dinghy stuff that may be correct, but not easy to figure out. Sail power has a lot of basic stuff that is still correct and is much easier to read and actually implement. Sail materials have changed, but as airfoils they still need adjusting to suit different conditions.


----------

