If this sail is too deep the fastflowing air will not be able to remainattached after the deepest parr of the sail and itwillseparpte

Different chord depths are important for different wind conditions in order to keep the flow of the wind attached to the sail. As a general rule of thumb, full sails (read lower chord-depth ratios) work better in light winds, and flatter sails (read higher chord-depth ratios) work better in medium to heavy winds. Using a full sail in a lot of wind will cause the fast-flowing air to separate from the sail (Figure 6.2). Flat sails can also work well in extremely light winds since they make it easier for the air to remain attached to the sail. If you try to make the sail too full there is simply not enough wind for the flow to even get around the corner, let alone to the leech.

The chart below gives you some idea of optimum chord-depth ratios for both mainsails and headsails. These are general estimates and should not be cast in stone. There are so many variables among boats of different designs that the numbers need to be manipulated to suit the conditions, but as a jumping-off point, these wind strengths and numbers are a good start.

Apparent Wind in Knots

Headsail Chord Depth

0-2

15-16 percent

3-12

18-19 percent

10-18

16-17 percent

16-23

15-16 percent

20-26

14-15 percent

24 +

12-13 percent

Apparent Wind in Knots

Mainsail Chord Depth

3-6

15-16 percent

6-12

14 -15 percent

12-18

12-13 percent

18-24

11 percent

24

10 percent

* Courtesy of North Sails

* Courtesy of North Sails

Figure 6.2.

With a chord-depth ratio too high, the flow of the wind cannot remain attached to the sail.

Figure 6.3

When the wind blows across a body of water the surface friction slows the molecules closest to the surface, which in turn have an effect on those molecules closest to them.

Figure 6.3

When the wind blows across a body of water the surface friction slows the molecules closest to the surface, which in turn have an effect on those molecules closest to them.

Was this article helpful?

0 0
Boating Secrets Uncovered

Boating Secrets Uncovered

If you're wanting to learn about boating. Then this may be the most important letter you'll ever read! You Are Going To Get An In-Depth Look At One Of The Most Remarkable Boating Guides There Is Available On The Market Today. It doesn't matter if you are just for the first time looking into going boating, this boating guide will get you on the right track to a fun filled experience.

Get My Free Ebook


Post a comment