I just came back this afternoon from a short, somewhat gnarly, daysail. Strider was plugging along just fine but I returned because working so hard alone (no one crazy enough to go with me on a day like this) and getting wet doesn’t have quite as much appeal after laying down over 2000 miles of GPS tracks this season as it did back in the spring.
I was surprised, as usual, to see that the buoy report only showed 20 gusting to 25. It always seems like it should have been more but that was consistent with what I was recording with a hand held anemometer while waiting to see if it would go down enough to make the dinghy row back easier. I think few sailors realize just how much wind this really is.
This got me to thinking about reefing and winds speeds. Needing something else to pass the afternoon, I came up with the following.
Strider is a bit on the tender side so, when all sails are trimmed to optimum power and she is at a comfortable heel angle, the wind speed will be about 12 knots. This will leave a few inches of freeboard amidships. With her hull form, I sail with a few more degrees of heel than flatter and more wedge shaped modern boats. If I ease the main, pinch up a bit to let the jib tell tales lift a bit, and accept a bit more heel angle, the full sail plan wind speed goes up to about 15 knots. After that, it’s time to reef. Reefing at 12 knots will get me to windward faster. I can, of course, carry full sail in considerably more wind if necessary but it means a lot of flogging and diminished efficiency.
I got to wonder what wind speeds correspond to various reefed sail plans if you assume the same “aggressiveness” in trim and heel angle. Since I have the sail plan in CAD and used to be a sailing vessel stability expert, it wasn’t too difficult to come up with the slide show below. The first slide shows “12 / 15” in the upper right which corresponds to the wind velocities mentioned above. Each subsequent slide shows a reduced sail plan and the wind velocities which would produce the same heeling moment (and thus heel angle) with the sail plan trimmed for full power and with the same amount of de-powering that lets me carry full sail to 15 knots.
Boats with more sail carrying power, either through weight distribution or hull form, will sail at lower heel angles than my E 32 but the relationships in the slide show will be about the same for similar sail plans. It’s interesting that reefed all the way down only about doubles the wind speed that the boat can handle easily. Twice the wind speed is four times the wind pressure, however.
This shows why 30 knots of wind is a lot for most boats. Much more and you probably aren’t going to make much progress to windward. There’s a reason why they start to call it a gale when wind gets much over this.
I was surprised, as usual, to see that the buoy report only showed 20 gusting to 25. It always seems like it should have been more but that was consistent with what I was recording with a hand held anemometer while waiting to see if it would go down enough to make the dinghy row back easier. I think few sailors realize just how much wind this really is.
This got me to thinking about reefing and winds speeds. Needing something else to pass the afternoon, I came up with the following.
Strider is a bit on the tender side so, when all sails are trimmed to optimum power and she is at a comfortable heel angle, the wind speed will be about 12 knots. This will leave a few inches of freeboard amidships. With her hull form, I sail with a few more degrees of heel than flatter and more wedge shaped modern boats. If I ease the main, pinch up a bit to let the jib tell tales lift a bit, and accept a bit more heel angle, the full sail plan wind speed goes up to about 15 knots. After that, it’s time to reef. Reefing at 12 knots will get me to windward faster. I can, of course, carry full sail in considerably more wind if necessary but it means a lot of flogging and diminished efficiency.
I got to wonder what wind speeds correspond to various reefed sail plans if you assume the same “aggressiveness” in trim and heel angle. Since I have the sail plan in CAD and used to be a sailing vessel stability expert, it wasn’t too difficult to come up with the slide show below. The first slide shows “12 / 15” in the upper right which corresponds to the wind velocities mentioned above. Each subsequent slide shows a reduced sail plan and the wind velocities which would produce the same heeling moment (and thus heel angle) with the sail plan trimmed for full power and with the same amount of de-powering that lets me carry full sail to 15 knots.
Boats with more sail carrying power, either through weight distribution or hull form, will sail at lower heel angles than my E 32 but the relationships in the slide show will be about the same for similar sail plans. It’s interesting that reefed all the way down only about doubles the wind speed that the boat can handle easily. Twice the wind speed is four times the wind pressure, however.
This shows why 30 knots of wind is a lot for most boats. Much more and you probably aren’t going to make much progress to windward. There’s a reason why they start to call it a gale when wind gets much over this.
My wind instrument captured a peak gust today of 36 while back on the mooring.
