You Don't Need Instruments to Find the Best Angle Downwind
You Don't Need Instruments to Find the Best Angle Downwind
John Alofsin explains how to sail by feel on the runs. "Boatspeed" from our February 1999 issue.
We're all familiar with the phrase, "Hey buddy, what's your angle? Everyone's got an angle." While the question clearly isn't aimed at sailing, it's still a good one for us. Having the right angle is the secret to sailing downwind.
When running downwind, there's a simple trade-off: you can sail directly toward the mark, but your boatspeed will slow as you head more toward dead downwind. Alternatively, you can reach up, away from the mark, to generate more speed, but you'll then sail a longer distance. Is the extra speed worth sailing the extra distance? That's the question you need to answer.
Choosing the best angle to the wind results in the greatest velocity made good toward the mark. The rule of thumb is to reach higher in lighter conditions (to keep up your boatspeed) and to sail lower as the wind builds. The range of apparent wind angles is huge, going from less than 90 degrees in light air all the way down to 180 degrees apparent in windy conditions.
Sight, Feel, and Hearing
When running, the clues to finding the best angle are subtle but plentiful, and you don't need electronic instruments to detect them. Let's say our instruments are limited to a masthead fly, perhaps a compass, and our five senses. We'll start with our senses since they do the same thing as the most sophisticated instruments: they gather information (data) which is then processed by our brain.
The three players involved in selecting a downwind angle are the helmsperson, the spinnaker trimmer, and the tactician. The trimmer, through "feel," is often the first to detect a change in wind strength. A puff will cause the spinnaker sheet to load up and tug, while a lull will have the opposite effect. The trimmer should tell the helmsperson about any change in feel or pressure. A comment from the trimmer that "I've got good pressure" should result in the helmsperson bearing off and sailing a more direct angle to the mark. As the boat bears off, the pressure on the sheet will lessen and the trimmer should tell the driver to "hold it there" before the sheet goes too soft.
How do you know what "too soft" is? If the helmsperson continues to bear off, the spinnaker will begin to droop and can eventually collapse. When you sail too deep, there's not enough apparent wind to pressurize the sail. If the trimmer says he's "losing pressure," the helmsperson needs to head up slightly and re-evaluate the sailing angle.
