Roger Ware
Member III
On the grounds that there is no such thing as a stupid question, what are draft stripes and should I have them put on my new mainsail?
Cheers, Roger
Kingston, ON
Cheers, Roger
Kingston, ON
Draft Stripes
- Thread starter Roger Ware
- Start date
NateHanson
Sustaining Member
Draft stripes are strips of contrasting material that are sewn in perpendicular to the luff, to make it easier to see sail shape and draft across the belly of the sail. If you're a moderately performance-oriented sailor then they're definitely worth the few bucks they cost. But if you're not likely to ever touch the outhaul, change halyard tension, or use a cunningham, then you could leave them off the order. The only real downside, aside from a few bucks, is that some people would say they look funny.
Stripes
Draft stripes are lengths (strips) of colored dacron tape, usually 3/4"-1" wide (varies with the size of the sail) which are laid onto the sail parallell to the waterline/perpendicular to the mast. The function is to give you a better "view" of the amount and location of draft in the sail.
Most boats will go with at least 2 stripes (upper and lower), some more serious sailors will go with 3 (lower, middle and upper). This way, it is much easier to visualize the draft at the various heights.
Generally you would like to see the maximum draft at the same percentage from the luff to the leech at each level. The actual distance of the max draft in terms of luff to leech will get shorter as you go higher (because the sail gets narrower as you go up), but you can use the stripes to help set the draft at the same (or nearly same) percentage..
Really they simply provide a contrast-the stripes are red, blue, black, green, etc.-as the customer desires-against the base fabric of the sail so that the depth(aka draft) and location of max depth is easier to see.
They are a good tool for optimizing sail trim.
How is that for early in the am?
S
Draft stripes are lengths (strips) of colored dacron tape, usually 3/4"-1" wide (varies with the size of the sail) which are laid onto the sail parallell to the waterline/perpendicular to the mast. The function is to give you a better "view" of the amount and location of draft in the sail.
Most boats will go with at least 2 stripes (upper and lower), some more serious sailors will go with 3 (lower, middle and upper). This way, it is much easier to visualize the draft at the various heights.
Generally you would like to see the maximum draft at the same percentage from the luff to the leech at each level. The actual distance of the max draft in terms of luff to leech will get shorter as you go higher (because the sail gets narrower as you go up), but you can use the stripes to help set the draft at the same (or nearly same) percentage..
Really they simply provide a contrast-the stripes are red, blue, black, green, etc.-as the customer desires-against the base fabric of the sail so that the depth(aka draft) and location of max depth is easier to see.
They are a good tool for optimizing sail trim.
How is that for early in the am?
S
Frank Langer
1984 Ericson 30+, Nanaimo, BC
Seth, for early in the a.m., it's brilliant!! 
Kim Schoedel
Member III
I found the draft stripes very helpful on our previous boat for sail trim. Had them on the head sail too so the two sails matched each other.
Up with Stripes
What those guys said!
And further, if your sailmaker cheaps out on their price quote and tells you that an Ericson emblem, a stripe, and numbers are all extra... along with "real good quality thread"... ya might want ta shop around quite a bit more.
We have always had all these "normal extras" since starting out with our first Ranger-20, 30 years ago. And none of our boats have been "racing" boats, although we have entered a few races with each boat we've owned.
And, if they further argue that "performance" and "quality" features only belong on a racing sail, and then they ask (with raised eyebrow) if you are one of "those" sailors... just excuse yourself, citing an appointment to get your nose hairs clipped.
Or, something...
Oops, gotta go. Time for my morning coffee.
Loren in PDX
What those guys said!
And further, if your sailmaker cheaps out on their price quote and tells you that an Ericson emblem, a stripe, and numbers are all extra... along with "real good quality thread"... ya might want ta shop around quite a bit more.
We have always had all these "normal extras" since starting out with our first Ranger-20, 30 years ago. And none of our boats have been "racing" boats, although we have entered a few races with each boat we've owned.
And, if they further argue that "performance" and "quality" features only belong on a racing sail, and then they ask (with raised eyebrow) if you are one of "those" sailors... just excuse yourself, citing an appointment to get your nose hairs clipped.
Or, something...Oops, gotta go. Time for my morning coffee.
Loren in PDX
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Controlling Draft
Tell me if my basic reasoning is correct. In reaching in stronger winds one wants less draft as far forward as possible (flat sail). To obtain this, tension halyard, cunningham, outhaul, BS, and vang. In lighter winds increase draft and move draft back by easing all of the above (full sail).
What about wind aft of the beam? Does the same flat shape on the main apply in high winds and full sail in light winds? Here we would do the basically same to obtain the correct shape with the exception of tensioning BS in high winds and keeping tension on the vang in light wind to keep the boom from rising?
Tony
Peregine Spirit
Erc 380 #16
Tell me if my basic reasoning is correct. In reaching in stronger winds one wants less draft as far forward as possible (flat sail). To obtain this, tension halyard, cunningham, outhaul, BS, and vang. In lighter winds increase draft and move draft back by easing all of the above (full sail).
What about wind aft of the beam? Does the same flat shape on the main apply in high winds and full sail in light winds? Here we would do the basically same to obtain the correct shape with the exception of tensioning BS in high winds and keeping tension on the vang in light wind to keep the boom from rising?
Tony
Peregine Spirit
Erc 380 #16
Frank Langer
1984 Ericson 30+, Nanaimo, BC
I would suggest that you also need to factor the traveller adjustment into all of the above, as a traveller to windward in light air can induce more sail twist and open the leech at the top to take advantage of the wind angle there. In stronger breeze, centering the traveller to get a straight pull down will flatten the leech and by eventually lowering the traveller to leeward, you can change the angle at which the wind hits the sail and likely reduce boat heeling. But Seth, Loren and others will likely add their expertise to explain this all more clearly....
Frank.
Frank.
NateHanson
Sustaining Member
I'm sure the pros will chime in soon enough, but I'll give it a go too, as much an exercise for myself, as a help to others.
You don't necessarily want to flatten the main or jib as much as possible, and get draft as far forward as possible when the wind pipes up. If you flatten the sail like a board with draft at 5%, you won't get any drive out of it. I think you just want to keep things adjusted so that whatever the wind conditions, the draft is 15-25% back, and depth is appropriate for the "gear" you want to be driving with. Often when the wind first kicks up you'll get an accompanying chop, and that requires a lower gear to provide power that keeps your speed consistent through the waves, and gets the boat accelerating between big waves.
In moderate wind conditions off a windward shore, giving you easy 10 knot breezes and glassy seas, you may actually want a slightly flatter sail than in the above chop and 15 knots, because you're sailing in a higher gear. You need very little acceleration, because the boat remains easily at a nice smooth hull-speed pace with no waves slapping at that cruising speed.
Sail twist plays into this too (more twist puts you in a lower gear), and that's controlled by jiblead position and traveller position when close hauled. When reaching main twist is controlled with the main sheet, and off the wind you control twist with the vang. But then it's less about power, and more about keeping control of the leach I think. The rule I've heard is just to keep that top batten parallel to the boom in a run.
You don't necessarily want to flatten the main or jib as much as possible, and get draft as far forward as possible when the wind pipes up. If you flatten the sail like a board with draft at 5%, you won't get any drive out of it. I think you just want to keep things adjusted so that whatever the wind conditions, the draft is 15-25% back, and depth is appropriate for the "gear" you want to be driving with. Often when the wind first kicks up you'll get an accompanying chop, and that requires a lower gear to provide power that keeps your speed consistent through the waves, and gets the boat accelerating between big waves.
In moderate wind conditions off a windward shore, giving you easy 10 knot breezes and glassy seas, you may actually want a slightly flatter sail than in the above chop and 15 knots, because you're sailing in a higher gear. You need very little acceleration, because the boat remains easily at a nice smooth hull-speed pace with no waves slapping at that cruising speed.
Sail twist plays into this too (more twist puts you in a lower gear), and that's controlled by jiblead position and traveller position when close hauled. When reaching main twist is controlled with the main sheet, and off the wind you control twist with the vang. But then it's less about power, and more about keeping control of the leach I think. The rule I've heard is just to keep that top batten parallel to the boom in a run.
Roger Ware
Member III
Brilliant - Thank You!
Wow - a dozen replies before lunch - this is some brains trust (or, its definitely not sailing season any more!). Thank you, my sailmaker (Quantum) had included them in the price, but I just wanted to make sure I understood what they were before I said yes. Actually I think I had them on my old mainsail, but obviously didn't use them.
best to everyone from a surprisingly mild Kingston.
Roger
Wow - a dozen replies before lunch - this is some brains trust (or, its definitely not sailing season any more!). Thank you, my sailmaker (Quantum) had included them in the price, but I just wanted to make sure I understood what they were before I said yes. Actually I think I had them on my old mainsail, but obviously didn't use them.
best to everyone from a surprisingly mild Kingston.
Roger