Sailing Up-Wind in Gusts

Feathering up:
An Alternative to "when in doubt, let it out"

Two important things happen when a gust hits your boat while you're sailing upwind:

First, and most obviously, the wind gets stronger and has the strength to overpower the boat and make it heel.

Secondly, more subtlely but more importantly, the direction of the apparent wind changes. The direction of the wind seems to be coming from further aft, more on the beam rather than on the nose.

 

Apparent Wind - (n) The wind experienced by a vessel which constrains its speed and course. The apparent wind is the vector sum of the "true wind" and the wind generated by the motion of the vessel.

 

The skipper has two ways to respond to respond when a gust hits. S/he can either head up so the boat's trim matches the new apparent wind direction or he can ease the mainsheet's angle of attack (by using the mainsheet or traveller, assuming that he boat has a traveller).

For many situations, the best response by the iikpper to being overtrimmed (because the appaent wind moved aft) is to keep a delicate touch on the tiller, and to let the boat head up so the trim of her sails matches the "new direction" of the apparent wind. The skipper keeps the sails properly trimmed and smoothly powered up just by smoothly steering up in the gusts and down in the lulls.

If you are close-hauled, stay properly trimmed by heading up when the gust hits and the apparent wind moves aft. When the gust subsides, the apparent wind moves forward again, and you should return to your original course. If you perform this maneuver properly, you work to windward at maximum efficiency.

The alternative when a gust hits is to "ease the main" (or in the case of a lateen, ease the only sail) -- that is, to follow the old "beginner's rule" of "When in doubt, let it out". But the problem is that when you dump wind with the mainsheet, all the airflow on the sail(s) is disrupted and the boat "lurches" back upright suddenly, and slows down.

When the boat slows down abruptly, the apparent wind direction shifts even further aft... and you have to start all over trimming from a "reach" when the boat is moving slowly, then trimming in the sails as the boat picks up speed and the apparent wind moves forward again.

Many people try to maintain the old course when a gust hits. They don't perceive that when a gust hits, the apparent wind moves aft, and the boat should be given the freedom to head up. If the boat is kept on the same (previous) course when a gust hits, she's overtrimmed and she heels precipitously.

In any sailboat, but especially in a light trailerable like the Potters (and all other lightweight trailerables and dinghies), it takes a light and perceptive hand on the tiller to feel how to let the boat find her own way in the gusts. When the skipper learns to feel the apparent wind shifts, and steer the boat accordingly, the boat sails faster and points higher.