Sail Material
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Sail Material
by skip241 » Fri Jan 14, 2005 4:57 pm
I've been sailing the EC12 for many years but cannot remember seeing any of the boats with drafting mylar sails. Is there a reason why other classes use this material and the EC12's don't? Thanks. Skip
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by s vernon » Fri Jan 14, 2005 6:28 pm
I have been thinking about this subject the last couple of days by coincidence and have a few thoughts. For info, John Bottensek, who does very in Florida, makes his own drafting mylar sails.
An observation at the Melbourne, FL regatta in early December. Reichard and Danny were there. They were flying TriSpi25 DT mains and jibs. I asked Danny about it and he said he likes to use them in wind up to about (I cannot remember but I think he said) 8 or maybe he said 10. The wind was light to medium with just one blaster race (relatively) last race on Saturday. I should have asked why he liked them, but like I said, I have ideas. I think those 2 highly skilled sailors like them because the flimsy sails give them absolute instant feedback about what is going on between the sails and the wind. Stiffer sails would not talk to the skipper as much - would be a tiny bit slower to luff. My opinion anyway. They are so skilled that they can react to every little nuance of wind and beneficial tiny change in sail trim.
Which brings us to drafting mylar sails. In a boat like my Odom, you trim the sails and the boat goes like mad or doesn't. If it doesn't you trim them in a little or let them out a little until the boat goes fast. My point is that speed is important not feedback from the sails. (At least that is the simpleton way to race the boat.) So sails that keep their shape like drafting sails are great in speed classes because they sit there always shaped and ready for the wind to hit them and the boat to take off. Also that solid white color makes the drafting film sails difficult to read/see when they do luff.
They might be great in EC12s too, but Drafting Film sails take a different sailing style - skipper has to be willing to race with less feedback from his sails. Anyway the EC12 is a finesse boat rather than a pedal to the metal boat so the desire for more feedback from the sails might be a reason why there are so few drafting mylar sails.
Doesn't Black Magick make Drafting Film EC12 sails?
Scott
An observation at the Melbourne, FL regatta in early December. Reichard and Danny were there. They were flying TriSpi25 DT mains and jibs. I asked Danny about it and he said he likes to use them in wind up to about (I cannot remember but I think he said) 8 or maybe he said 10. The wind was light to medium with just one blaster race (relatively) last race on Saturday. I should have asked why he liked them, but like I said, I have ideas. I think those 2 highly skilled sailors like them because the flimsy sails give them absolute instant feedback about what is going on between the sails and the wind. Stiffer sails would not talk to the skipper as much - would be a tiny bit slower to luff. My opinion anyway. They are so skilled that they can react to every little nuance of wind and beneficial tiny change in sail trim.
Which brings us to drafting mylar sails. In a boat like my Odom, you trim the sails and the boat goes like mad or doesn't. If it doesn't you trim them in a little or let them out a little until the boat goes fast. My point is that speed is important not feedback from the sails. (At least that is the simpleton way to race the boat.) So sails that keep their shape like drafting sails are great in speed classes because they sit there always shaped and ready for the wind to hit them and the boat to take off. Also that solid white color makes the drafting film sails difficult to read/see when they do luff.
They might be great in EC12s too, but Drafting Film sails take a different sailing style - skipper has to be willing to race with less feedback from his sails. Anyway the EC12 is a finesse boat rather than a pedal to the metal boat so the desire for more feedback from the sails might be a reason why there are so few drafting mylar sails.
Doesn't Black Magick make Drafting Film EC12 sails?
Scott
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by Al Stein » Tue Jan 18, 2005 12:42 pm
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">In a boat like my Odom, you trim the sails and the boat goes like mad or doesn't. If it doesn't you trim them in a little or let them out a little until the boat goes fast. My point is that speed is important not feedback from the sails. (At least that is the simpleton way to race the boat.) So sails that keep their shape like drafting sails are great in speed classes because they sit there always shaped and ready for the wind to hit them and the boat to take off.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">I think you've painted just about the whole picture in your post... some of it maybe hidden in little pieces.
Yes, to get the boat going, yanking the sheets and watching the spray will do the job, but get it going as fast as it can under the conditions (or close to that fast) has to take a bit more because the act of going fast changes the conditions that the boat actually sees.
For example, a boat wants to sail across the wind -- it starts out dead in the water with the wind abeam, coming right over the starboard rail at 90 degrees from the center line. Pull the sail in to 45 or so and it takes off like a rocket, but...
Let's say the wind was about 10 kts and your boat has accelerated to 5 kts... the effect of your moving observation platform (i.e. the boat) is enough to move the direction of the apparent wind by about 30 degrees to the left and increase its speed by 10 or 11%. That is a BIG change in the conditions the sails are experiencing. We can't just set a sail, turn 30 degrees without adjusting it, and expect the boat to continue to perform well, but that's exactly what the sails think is happening.
So, every acceleration ruins your sail set. Therefore, if you successfuly find a setting that speeds up your boat, the speed-up will make that setting no good anymore. However, if you watch the fill and the twist of the sail as the relative wind changes, you may be able to continuously adjust for the new wind conditions before the boat has a chance to slow down. So if you can just tell directly how the sail-wind interaction is going, you get to continue going fast all the time instead of waiting for a slow-down to tell you it's time to trim or ease the sail.
OK, so that would be nice, but how do you know when the wind and sail interaction is changing? You could do that through good use of telltales or by watching the sail as it conforms to the change.
So that's one reason why a sail that changes with the changing apparent wind can be a good thing. It's about efficiency, so it's more a racing thing than a weekend cruising thing... but it never hurts and if you're going to race you may as well win, right?
<b><i> . . . Aim High!</i></b>
Yes, to get the boat going, yanking the sheets and watching the spray will do the job, but get it going as fast as it can under the conditions (or close to that fast) has to take a bit more because the act of going fast changes the conditions that the boat actually sees.
For example, a boat wants to sail across the wind -- it starts out dead in the water with the wind abeam, coming right over the starboard rail at 90 degrees from the center line. Pull the sail in to 45 or so and it takes off like a rocket, but...
Let's say the wind was about 10 kts and your boat has accelerated to 5 kts... the effect of your moving observation platform (i.e. the boat) is enough to move the direction of the apparent wind by about 30 degrees to the left and increase its speed by 10 or 11%. That is a BIG change in the conditions the sails are experiencing. We can't just set a sail, turn 30 degrees without adjusting it, and expect the boat to continue to perform well, but that's exactly what the sails think is happening.
So, every acceleration ruins your sail set. Therefore, if you successfuly find a setting that speeds up your boat, the speed-up will make that setting no good anymore. However, if you watch the fill and the twist of the sail as the relative wind changes, you may be able to continuously adjust for the new wind conditions before the boat has a chance to slow down. So if you can just tell directly how the sail-wind interaction is going, you get to continue going fast all the time instead of waiting for a slow-down to tell you it's time to trim or ease the sail.
OK, so that would be nice, but how do you know when the wind and sail interaction is changing? You could do that through good use of telltales or by watching the sail as it conforms to the change.
So that's one reason why a sail that changes with the changing apparent wind can be a good thing. It's about efficiency, so it's more a racing thing than a weekend cruising thing... but it never hurts and if you're going to race you may as well win, right?
<b><i> . . . Aim High!</i></b>
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