How to fix a shitty sail/mast combo

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I'm curious; why don't you use the old mast that works?

It is silly to buy a mast not specified by the designer. You are throwing away money to do otherwise.

Bill Kline Gorge Sport USA Curtis Performance Fins, Orca Fins, Orca Kite Fins Hood River, OR USA

ph/541 387 2649 fax/541 386 1715

Thankyou for the discussion on this.. helpful.

Some however are missing more point. Ellen I do not have the resourses (financial) to purchase a new mast with every sail I buy. So I improvise. As Roger pointed out the VTS system can often be misleading as masts may differ slightly, and as in my case, will differ, as I choose not to buy another mast for the sail. The whole point I guess is forget mast/sail recomendations (as I cannot meet them), but supply me with depth, draft, position settings as they would be on the recommended mast. I can then try to emulate them using the equipment I have available. (Excelerator 460 mast) Thanks for the help tho. Is there any broad guidelines for max depth for sail sizes?

Gary Tayler Bayside, Melb, Australia

Roger, Thanks for that info. Did a read on the sail specs of that Spectro and your are right about the mast flex. They recommend their mast which is soft top and bottom, constant flex I think they called it. I use an Excelorator 460 which I bought for my Specro 7.0, as you see great for the 7.0 but crap for the 6.0. I guess you would think the Specro range would require similar masts, whoops.. silly me. Thanks again for the help.

Gary Tayler Bayside, Melb, Australia

Hello Gary, Hmmmm.... something is very wrong here. The North Excellerator 460 either the Excellerator 60 or the Excellerator 80 is precisely the 'best' mast for any Spectro that recommends an Excellerator

460 mast. The very last Spectro's used the Constant Flex Top (CFT) system, but the earlier Spectro's used a full Flex Top (FT) mast. Could it be that the Spectro's you have are from different years. Seems I remember that the 5.5 Spectro rigged on an Excellerator 430, the 6.0, 6.5, 7.0, and 7.5 rigged on the Excellerator 460, and the larger larger sails rigged on the Excellerator 490. So, what I'm suggesting is that you must have 2 different year models, and the mast specifications may have changed with the change of year models. Otherwise, both sails should rig perfectly on the same mast.

I keep hearing you say you want a draft depth specification. Sorry, but no one I know measures this. You could stretch a string from tangent to the luff sleeve, to the clew, and measure the depth of the draft, but where? At which batten, and in what state of tune. Far too difficult to measure accurately and repetitively. Use the VTS tuning system, or the 'batten drop' method, which are far easier,

and very easy to duplicate your settings, or easy to set for what you think the

conditions are. If you know what year your sails are (you might be able to pull that info out of the serial number) I have some old North catalogs, and may have a Spectro tuning guide or 2. Have you checked your sail bags to be sure there isn't a printed guide in the little pocket near the zipper on the bag? This would tell you for sure what year your sails are, and how to tune them. Hope this helps, Roger

OK, I'm confused here. I thought the reason for all this was that you bought a new mast! Why not replace an old mast with a mast that is designed for your sail? I realize that it is too late now, but you are merely putting patches on. Unless someone with the same sail and mast that you have sits down, rigs up, and measures all this, it will be difficult to provide you with an answer. Why not rig up yourself and fiddle with the tuning until you get it right. None of us will be able to duplicate your conditions. Sorry to be so unhelpful.

The draft magnitude is a function of chord (boom length) and other than sail size and wind velocity determines the power. You will find a method for checking and setting the draft at this URL:
http://www.windwing.com/riginstr.html#anchoradjouthaul

The chordwise draft position (on the right mast) is a function of your sail's cut, batten stiffness and taper. Normally the max draft should be in the range of 25-45% from the front of the mast. You can vary the position some with downhaul but if you attempt to do this by under or overdownhauling outside of the normal settings or changing to a non-spec mast, the performance and handling will be compromised.

The draft position primarily effects the balance and handling and using the correct mast (or one close to it in stiffness and flex) is the best way to insure you get on the water what the sail's designer intended.

Get a straight edge, tape measure and go to work on it...

Best regards, - Bill

I'm very surprised by your statement - especially from a recognized NG and industry 'expert' upon whom many rely to help make their equipment decisions. What is inaccurate and non-repetitive about a straight edge, a tape measure and some basic math?

Where to measure? Anywhere on the body of the sail that is of interest! If you want to find an appropriate boom/outhaul setting then that would certainly be a good place to start. If you are wondering about the mast flex curve you can measure the draft at several locations along the luff to check the spanwise distribution and compare it to the distribution on the proper mast. The variations will be diagnostic regardless of outhaul or VTS setting.

The VTS, 'batten drop' or any other subjective visual loose-leech method of rigging a sail is directed at setting the downhaul and associated twist/handling and is independent of draft under dynamic load. That is why you and many other dedicated performance-minded sailors have adjustable outhauls - to vary the DRAFT!

Measuring takes time but is far from meaningless unless you want to take it to the Heisenberg level...

- Bill

Hello Bill, Yes, I agree with you completely, I, we, anybody could measure the draft, calculate the percentages, crunch the numbers, and come out with a chart of the draft characteristics, at any location, on a particular sail. I believe most sails are designed on computers somewhat this way, are they not? The computer programs need the numbers to generate the shapes between the measurement 'stations' throughout the entire sail. The problem here, is that how do we get Larry Herbig to give us the original numbers, and since this gentleman had a sail that worked the way Larry designed it, changed the mast, and now he no longer has the same characteristics. This would seem to indicate that the new mast is pretty much wrong for the sail, would it not? And, since the North Spectro was one of the few WS sail designs, that you could truly 'rig by the numbers' (simply put in the correct mast, set your base for the needed extension, and set your boom to the right length, Outhaul, Downhaul, and go sailing) how the heck do we get him to quit trying to redesign the sail to work on an obviously incompatible mast. He doesn't just want a number for rigging purposes, he wants the numbers so he can see whether his smaller sail has all the same draft characteristics as his larger sail. It would seem to me that they would not have the same kind of numbers as they are 2 different sizes. I also have a gut feeling that something else is going on here. Maybe he's not using a mast extension, or has the vario head cap stuck down inside the head of the sail, or something. Spectro's are/were very easy to rig correctly, by the numbers, and the sizes he is talking about rigged perfectly on the same North Excellerator 80 460cm IMCS24-26 CFT mast when I used these sails a few years ago. I've been trying to draw him out to find out what it is that he's doing that made a sail that he loved, into a sail he won't even think of using, just by getting a new mast. It would seem the 'problem' here is something he is doing differently. Regards, Roger

Hi Roger:

Glad we agree.

In Gary's original post he had already made measurements with different masts and found significant differences in the draft vs VTS settings on different masts. He logically asked for general guidelines so he could educate himself. He repeated the request on 12-08. Your response was that nobody does this (but he already had) and that it was difficult to do accurately and repetitively. From my point of view, his questions were valid and directed at the relationship between mast flex and sail shape as well as how a sail should best be rigged in terms of draft. This requires measuring - not looking at silk-screened downhaul indicators on the head of a sail.

You were certainly being helpful and it is very commendable - just don't advise those who wish to understand in detail to throw away their tape measures...

- Bill

Sorry to cause the reging debate, so consider this the last on it (unless you disagree with me!) I iniatially was trying to come up with a set 'formula' for position, height and depth for a sail. I tried this on all my sails 5.0, 6.0 and the 7.0. I used the string and tape measure system and recorded everything I could think of. I tried it on two masts 1 I own and one dont anymore (Ellen thats the reason). I entered the info into a spread sheet and was conmparing the settings on each. My original post didnt contain all the info as I think I said I didnt want to bore anyone. The result is that their is common traits among sails and masts. Position of the max draft does change (of course!), but quite predictablely according to my calculations. I wanted from the group an 'estimate' of what was considered normal. Given a sail I dont have say a 4.5, using the spreadsheet, I think I could estimate quite well the details of the draft position. That was the whole reason I did the exercise. The one thing that doesnt change by the way is the height of max draft, I guess its set in the sail cut.

So.. the last word is at 3.am a front came through, and right now at 8.15am its blowing 28 knots and I'm going sailing. It's what we all are here for isnt it. Thanks for the feedback.

Gary Tayler Bayside, Melb, Australia