upwind Genoa trimming - lighter airs - SailNet Community
 
LinkBack Thread Tools
post #1 of 10 Old 07-06-2004 Thread Starter
Senior Member
 
mikehoyt's Avatar
 
Join Date: Nov 2000
Posts: 687
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 15
 
upwind Genoa trimming - lighter airs

Me again. Boat is still a 26 foot fractional rig. Has forward tracks for a blade and genoa tracks for the 150 kevlar genoa. Sails are all new.

It has been suggested that with a kevlar sail there is little or no stretch so halyard adjustments on this genoa are not used to any degree. It seems then that my two most useful controls are the car positions and the sheet.

I have my genoa trimmed normally to have the inner luff telltales all breaking at the same time. Normall I have the leeward telltales streaming and the windward telltales just starting to break. I am thinking that I should probably be moving the cars forward in chop but other than that I am not as certain how to trim this sail for optimal upwind performance in light air.

Any genoa trimming for dummies advice to make this go faster upwind? Currently I point about as high as most boats in the fleet but there is always that one boat in any given condition that points higher while going as fast. My job is to determine what I can do to improve that little bit more....


Thanks again,

Mike
mikehoyt is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 10 Old 07-06-2004
Member
 
Join Date: May 2003
Posts: 45
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
upwind Genoa trimming - lighter airs

The key to pointing as I understand it is to reduce the side forces that cause leeway. You reduce the side forces by moving the center of effort forward. Things that do this:

- Closed leeches on both sails--achieved with strong sheeting (possibly twings on jibsheets if no lateral cars)

- In strong wind, increase mast bend--achieved with backstay tensioning

- In low wind, decrease mast bend

- Uppermost main telltales should be just at stall;

It''s also important to figure out if you have excessive leeway or not. Which is a subjective question that depends on your boat, but for most racing boats would be around 5 degrees I''m guessing. If it''s a leeway problem, then you might need to hike harder (get bigger crew!), and you might need to experiment with adding more cunningham and outhaul while easing the sheets a bit.

On the other hand, it''s good not to get obsessed with pointing to the exclusion of watching your overall VMG. After all, a boat in irons is pointing perfectly. :-) Some boats will beat you by sailing lower but faster over the entire course.

bw
bob_walden is offline  
Quote Quick Reply Share with Facebook
post #3 of 10 Old 07-06-2004
Member
 
Join Date: May 2003
Posts: 45
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
upwind Genoa trimming - lighter airs

The key to pointing as I understand it is to reduce the side forces that cause leeway. You reduce the side forces by moving the center of effort forward. Things that do this:

- Closed leeches on both sails--achieved with strong sheeting (possibly twings on jibsheets if no lateral cars)

- In strong wind, increase mast bend--achieved with backstay tensioning

- In low wind, decrease mast bend

- Uppermost main telltales should be just at stall;

It''s also important to figure out if you have excessive leeway or not. Which is a subjective question that depends on your boat, but for most racing boats would be around 5 degrees I''m guessing. If it''s a leeway problem, then you might need to hike harder (get bigger crew!), and you might need to experiment with adding more cunningham and outhaul while easing the sheets a bit.

On the other hand, it''s good not to get obsessed with pointing to the exclusion of watching your overall VMG. After all, a boat in irons is pointing perfectly. :-) Some boats will beat you by sailing lower but faster over the entire course.

bw
bob_walden is offline  
Quote Quick Reply Share with Facebook
post #4 of 10 Old 07-07-2004
Senior Member
 
paulk's Avatar
 
Join Date: Jun 2000
Location: CT/ Long Island Sound
Posts: 2,602
Thanks: 4
Thanked 26 Times in 25 Posts
Rep Power: 16
 
upwind Genoa trimming - lighter airs

New kevlar sails? Where''s your sailmaker to give you the quick rundown?
paulk is offline  
Quote Quick Reply Share with Facebook
post #5 of 10 Old 07-08-2004 Thread Starter
Senior Member
 
mikehoyt's Avatar
 
Join Date: Nov 2000
Posts: 687
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 15
 
upwind Genoa trimming - lighter airs

200 km from the boat.

I am looking for generalized adjustment rules here. The specifics for a particular sail I get from my sailmaker and experience (ex. this particular sail does not move well when sheeted too tightly)

Mike
mikehoyt is offline  
Quote Quick Reply Share with Facebook
post #6 of 10 Old 07-08-2004 Thread Starter
Senior Member
 
mikehoyt's Avatar
 
Join Date: Nov 2000
Posts: 687
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 15
 
upwind Genoa trimming - lighter airs

200 km from the boat.

I am looking for generalized adjustment rules here. The specifics for a particular sail I get from my sailmaker and experience (ex. this particular sail does not move well when sheeted too tightly)

Mike
mikehoyt is offline  
Quote Quick Reply Share with Facebook
post #7 of 10 Old 07-11-2004
Senior Member
 
Join Date: Feb 2003
Location: New England USA
Posts: 261
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 13
 
upwind Genoa trimming - lighter airs

In general, regardless of sail construction or material, you have two primary controls for a headsail, lead position and luff tension. Newer modern composite materials and shapes just respond to a narrower range of luff adjustments.

Rig a cunningham and lead it back to the cockpit. No cunningham hole in the jib? you are restricted to halyard tension adjustments, which may be limited due to the hoist.

Playing with luff tension is not something to be done during race day. You need to be able to make adjustments and note their affects without having to worry about the competition. You also need to remember that what works for a Light #1 may not work with your other sails and you should try and go out and check each sail in its recommended wind range.

Set you sail, then make an adjustment to the luff tension, go forward and note the draft position. TAKE NOTES! Write down the lead position, luff tension, wind speed and angle, helm, boatspeed, sea conditions, etc.

Now you are armed with the baseline data for that sail.

OK. There are three sea conditions you will have to deal with, swell, chop from stinkpots and glassy smooth. Each requires a different technique. Mastery of them is what separates the "men fom the boys" (Sorry, ladies, it''s just a term coined by the oppresive male dominated sport, but I digress...)

In chop, you will want your draft farther aft, for a fuller, fatter shape. Helping you power through the slop. You don''t want to be trying to point at your highest possible angle either. DON''T PINCH!!!! Full and fat is faster in slop.

In swell, you need your skipper to really be in synch with the waves, taking into account the changes in appearant wind angle as the boat climbs the waves and acceleates down the back side. Draft in its middle position will help average out the changes.

In glassy conditions, draft forward and ultimate concentration are the thing.

In every case, crew movements should be minimized, and in chop, they should be grouped together near the center of the boat. Crew out at the ends or spread out will adverersly affect the boats motion.

Tacking is an artform in the light stuff. Rudder motions should be s-m-o-o-t-h and s-l-o-w, to try and maintain as much boatspeed as possible. In swell, begin your tack at the trough, using the backside to help you accelerate on the new tack. I chop, try to find a flat spot, or at least to avoid hitting chop as you cross the wind. Once on the new tack, NEVER SHEET ALL THE WAY IN. You need to build speed and power FIRST, stay fat and low, and trim in and point higher only as your speed increases.

Also remember that in light air, the dirty air from other boats covers a much greater zone than in fresher breezes. Tack to clear air as soon as you can. Also remember that you will take longer to return to speed, so dont get into a tacking dual, or take too many tacks. Go for speed and clear air, and let the others do battle and slow thamselves down.
Silmaril is offline  
Quote Quick Reply Share with Facebook
post #8 of 10 Old 10-07-2004
Junior Member
 
Join Date: Oct 2004
Posts: 6
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
upwind Genoa trimming - lighter airs

No one has mentioned the key control for pointing in lighter airs. Headstay sag, all other factors considered, is paramount to pointing. Another possibility (in flat water) would be inboard Genoa tracks. Try softening the headstay considerably. Remember you need power to point, press the boat down until she''s up to speed, let the keel go to work and only then start letting the weather tickler lift-and only rarely in light air. good luck
SandyNicholson is offline  
Quote Quick Reply Share with Facebook
post #9 of 10 Old 11-25-2004
Senior Member
 
39512's Avatar
 
Join Date: Mar 2004
Posts: 101
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 12
 
upwind Genoa trimming - lighter airs

It seems your premise not to adjust the halyard is faulty. With appropriate headstay sag, it is a very important contol for headsail fullness, which is what you want in light conditions. Wrinkles can be your friend. Lead position is also critical. On our boat in light air, point is best when the foot is fairly far outboard, almost touching the lifelines.

Since you say you can point with most of your competitors save that "one" that is higher and faster, I would suggest that you do not chase him up to the detriment of your own boatspeed. Put the bow down and sail fast.
39512 is offline  
Quote Quick Reply Share with Facebook
post #10 of 10 Old 11-25-2004 Thread Starter
Senior Member
 
mikehoyt's Avatar
 
Join Date: Nov 2000
Posts: 687
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 15
 
upwind Genoa trimming - lighter airs

I have been reading this with interest.

At the beginning of 2004 I was letting off backstay tensioner almost entirely and easing both halyards (esp main) in light winds. Boat was definitely faster using 150 when we pointed off the wind a bit.

Later in season I tried tuning the rig (DUH!). Paid off a lot as then tension on the inners, outers and forestay was far lower than I had expected. However we also stopped playing with the jib halyard other than to just remove the vertical wrinkle if too tight or any scalloping if too loose on a windier day.

As you can imagine the results were a bit inconsistent. I am thinking that given a bunch of years I will finally learn the sail by about the time it is dead.

Another very interesting tactic was using a different helmsman and spending my own time adjusting the sails. This seems to have worked very well but was at end of season so difficult to measure. Will be tactic for next season. Very difficult to let go though as the helsman learns the boat ...

Thanks

Mike
mikehoyt is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome