March 23, 2014

Sailing in the Middle of the Fleet - Sailing Downwind Part 2

By Doug
More comments and questions from Pam. 'The sailing by the lee explanation finally clicked with me - but how far do you trim the sail in or out to make this work?'

It's a great question because sailing normally, when the wind flows from the luff to the leach, you trim and steer by looking at the telltales and the front of the sail. Does this mean that we need telltales at the leach for sailing by the lee?

The answer is no because people sailing by the lee rarely look at the sail. You sail by trying to feel the maximum pressure on the mainsheet. With the ratchet turned off this pressure will sometimes double, but it does not last long. Your goal is to hold this extra pressure for as long as you can - 5 seconds if you're lucky. You then let your sheet out a little before pulling it in again.

This action is very gentle and is not pumping but this extra pressure is not always easy to find. The lighter the breeze, the harder the extra pressure is to find and below 10 knots, it might not be possible for a beginner to find at all. When it does work your sail is actually generating lift instead of just catching the wind by stalling, which is what it's doing when your boom is out.

As a rule, you'll feel the strongest pressure just before the sail wants to jibe. Here's Tom Slingsby from the Perth Worlds video (at 21:02) where his leach is folding and the sail wants to jibe: 

Tom heads up to prevent jibing, but only slightly because his trim is fast.
So remember, sailing by the lee without the extra pressure can be slow. If you cannot find it within a few seconds, it's best to let the boom out to its regular "stalled" position and then try again in 10 seconds. It's a constant search for extra speed, which is another reason why it's so good for middle-of-the-fleet sailors. 

Sailing on a run downwind the with the boom out is like taking a break. Sailing by the lee makes you more aware of what your boat is doing and gives you things to try when other sailors are taking a break.

This post is about how to make it work. Our next post will be why it works and will include gifts from laws of physics: perfectly legal pumping.


  1. This is a great post - the light went on for me. I have often been sailing by the lee - with the telltales flowing in but apparently going no faster than others. I have occasionally felt the boost in speed you refer to - probably just by luck or a wind shift. But now I understand that it is something you have to keep looking for. I can't wait to get out on the water and try it out. Thanks!

    1. You're more than welcome. In Oman the conditions for this were marginal. It really helps to have a light air mainsheet as it improves the chances of this working.


    2. What do you mean by a light air mainsheet?

    3. If the conditions look light, I always take out a second mainsheet - one that goes a lot smoother through the blocks and does not weigh as much as this keeps it out of the water. I don't know the diameter but it's usually by far the smallest in the fleet.

      I decide just before the start which one to use. Keep in mind that it's easier to switch from regular to light than light to regular because with the latter, the breeze is filling in and it can be difficult (see Day 6 of the 2006 Master Worlds when I really needed help).

      Also, always take out a pair of gloves just in case the breeze fills in during the race.

    4. In my view a light air mainsheet is 6mm (I use the Rooster Polilite) and regular mainsheet is 7mm. I find I'm using the 6mm in increasingly stronger winds, the only drawback being that the 6mm has slightly more tendency to pick up a knot than the 7mm.

    5. Thanks for your numbers.

      And yes, the lighter mainsheets to tend to get more tangled, which is why I have side cleats. Approaching the windward mark, I cleat the main and then run it through my hands (without looking) because undoing a knot then is much easier than after rounding the mark when everyone is passing you.

  2. Do you find that the cleats are uncomfortable in light air forward sitting position?

    1. Yes, and a good reason to have cleats in (towards the center) as much as possible and a design that is as low as possible.


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