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Sail trim for reaching

Postby David E on Wed Feb 08, 2006 10:56 am

There has been quite a lot of discussion on the forum about sail trim close hauled but not much that I can find for reaching. I have difficulty with deciding optimum boom angle and dont know if sail telltails are used to trim when reaching.
David E

Postby Guest on Wed Feb 08, 2006 4:41 pm

Telltales should always be your guide for sail trim, upwind, reaching and running.

Things to look out for:
- Never stall out the top leach telltale
- Carry as much vang as you can without stalling the top leach telltale
- Try to get the telltales streaming off the wind as you would to windward.
- Sail the boat flat, you will go faster with less mainsheet and the boat flat
- If in doubt ease rather than pull on both the vang and the mainsheet
- Work harder - you can never work to hard off the breeze - big gains to be made...

Sail Trim on reaches

Postby Alan Riley on Wed Feb 08, 2006 5:14 pm

Hi David,

Good question. You are right, most people concentrate on upwind speed and trim but ask little about down wind and reaches.

On a close reach, use your telltales the same as for upwind. Use your vang to set the overall fullness of the sail, let the outhaul off a little bit (but not too much), and let the downhaul off until the front of the sail starts to wrinkle a bit. The mainsheet is then used to control the angle of the sail to ensure the telltales are all streaming.

On a broad reach it's more difficult because the boom and sail are limited in how far out they can travel by the side-stays. Let the outhaul nearly right off (ie. make the sail really full down low), and the downhaul off until the sail starts to wrinkle a bit. For me, however, the top telltales are the most important on a broad reach and the boom vang is the most important control. On a broad reach the bottom of the sail is generally stalled because the boom can't go out far enough. But if you let your vang off a bit, the sail will twist so you can still get some flow over the sail and keep the top telltales streaming properly. The trick here is to play the vang while going downwind. Being a high aspect ratio sail, it is very sensitive to wind pressure. Thus, when a gust hits the sail twists way too much and you lose power, so you must pull the vang on to control the twist. This is especially important in strong winds, because if you let the sail twist too much it develops power in such a way that it will roll you in to windward! Conversely, when the gust dies, your sail will stall unless you let the vang off again to let the sail twist and get the top flowing again. All of this needs to be co-ordinated with heading up a bit in the lulls, and bearing away in the puffs.

Do all of this, and you will not only have lots of fun, you'll go very fast downwind too!

Alan Riley
Sabre 1564
Alan Riley

Postby David E on Thu Feb 09, 2006 9:25 am

Thank you both for your advice. Its nearly more than I can comprehend at my stage of development but I will try it at the next opportunity. Its fantastic to be part of a group thats so generous with advice. Next time I meet you Alan I will let you know how I went. To date I have never used much vang except to stop the boom from lifting when off the wind. To windward with the Hooper sails I have used any vang pressure seems to close and hook the leech, so I am probably doing somthing wrong there also
David E

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