Sailboat Racing Trim — Part 8

In Chapter 8 of his book Racing Trim, Bill Gladstone talks about Upwind Trim Solutions. The following post shows a short summary of that chapter.

 

Remember that previously this book taught us that total power comes from the combination of the main and the jib.  The right amount and balance of power can be achieved with angle of attack, sail shape (depth), and twist.

 

Moderate Air Sailing

In moderate air, maximize lift by trimming to a near stall.  Then, fine tune trim of the sheet, depth, and twist.  Driving in these conditions should include small adjustments to gain point without losing speed.  Telltales can be used to trim for acceleration, full speed, and pointing.  Acceleration mode takes advantage of a wider angle of attack to build speed.  From full speed, the boat can be driven up further to achieve more point.  Be careful not to lose speed from too much pointing.

 

Light Air Sailing

In light air, the driver can help by increasing angle of attack (e.g. foot off) to add power. Ease the sheet to widen angle of attack (but not too deep or flow won’t stick with the sail). You could also ease the sheet.  In extremely light air, make the sail flatter to encourage air flow to stick with the sail.

 

Heavy Air Sailing
Reduce total power (when winds are too strong) by flattening sails, increasing twist and reducing angle of attack.  Then, reduce sail area if winds are still too strong.
The following table covers some trim solutions that were discussed in this chapter.
        Boat Performance Recommendations
Slow–  pointing OK, but not going fast
  • Add depth for extra power or
  • Add twist for better airflow over the sail
  • Try a deeper shape (but too deep will hurt speed)
  • Trim the jib a little harder & experiment with getting the outer lower telltale to dance
Low, but can’t point
  • Sheet harder
  • More main & less jib
  • Bigger genoa
Slow & Low
  • Over trimmed or under canvassed?
  • Move jib leads back to reduce drag
Rounding Up
  • Reduce power
  • Try more twist
Mushy Helm
  • Add speed — ease sails to let speed build & then trim in
  • Add power
Hyper Critical Groove, with inside telltales spinningone moment, and outside telltales dancing the next
  •  Widen the groove — tighten halyard or ease genoa sheet a few inches
Hyper critical power — slammed down one moment& luffing the next
  • Try more twist — your sails are filling & dumping
  • Try smaller jib & more powerful main
Pitching
  •  Get more power — sail lower or add depth to your sails
Pounding in waves
  •  Add twist to power through
  • move crew weight to see if that helps
Unable to point in bow-on waves
  •  Add twist
  • Use a bit more weather helm
Unable to point n beam-on waves
  •  Add weather helm
Fast on one tack, slow on the other
  •  Watch wind shear from mast head to deck — you may need to sail with mast head in irons
Remember that different boats respond better to different methods of trim.  Just because one method works really well on a given boat; it may not work well at all on a different boat.  Experiment until you figure out what works best for the boat your on and the conditions that day.

This is the eighth in a series of posts based on Bill Gladstone’s book Racing TRIM from the North U. Series.  Periodically, I post about a chapter or two.  This will be my short summary of what I’ve read.  You can read the posts to get my abbreviated summary; or you could read through the books with me.  Your comments can help point out what you find most interesting, or even poke fun at what I do and don’t know.  If you are interested in getting this book, you can find it in the online store section of NorthU.com for $25.