Lots of threads about sails not working with masts both now and historically so I did an ai deep dive to confirm brand differences.
If a brand is not listed I couldn't find the data.
What stands out is that every brand uses a different bend curve. Some brands it varies depending on mast length. Some brands also change from year to year meaning some pros get new masts from year to year. What stands out is whilst there are the rare crossovers it doesn't take much before a mast goes from being ideal to not so ideal.. Designers wouldn't design to 0.5% unless it made a difference to them. Not to say as punters we need to be within 0.5% but looking at the numbers below more than 1% and we may not like the results. Additionally the data below does not take into account variations in stiffness, taper and outside diameter which are also different from brand to brand and within each brands range.
and the real issue which is hiding in plain site. all the data below is taken by measuring the mast and not what happens when you load up the mast with the correct downhaul tension. Even though 2 masts may have the same bend curve percentages they will perform differently due to luff curve, carbon content, reflex, taper etc etc. yes it's a minefield.
Hoping more brands make their numbers available however I get it's IP.
Powerex 64/76
Unifiber cc 62.5/76
Unifiber fh 64/79
Unifiber fl 62/77
Duotone 61-63/75-77 depending on length.. the sls varies from year to year to suit sails.
Goya 340 - 65/78, 370&400 - 64.5/79, 430 - 64/78, 460&490 - 64/77
Neil Pryde 400 to 490 - 61/77 not confirmed.
North (pre 2017) 63/75-76 3di era varies.
S2 Maui 63-65/74-76
Ezzy 62/77
No limitz original 64-64.5/77-77.5, Sumo (stiffer imcs) 370 - 64/78.5, 400&430 - 64.5/77, 460 - 64.5/76.5
Sailworks - same as nolimitz sumo.
both point 7 and severne use different points to measure their bend curve..
Excellent topic !. And good info. Thanks mate.
For some, this complexity has killed Windsurfing. Some others, it's made the sport more interesting. I embarrass the extra complexity.
I would "guess" that sails have a higher manufacturing error than masts. Therefore, it would be easier to change the mast in order to fix tuning issues of a given batch of sails.
I think the Severne +7 point thingie may be marketing. I spoke to a mast manufacturer once that specified with 3 points (I won't mention the unit they used, as I don't want to create any friction between them and Severne). They said they produced masts for Severne, and others. This was the time period when Severne were marketing this 7 point thing by a few years. If you are outsourcing a part, how can you tell a fabricator to specify +7 points, when their tooling is 3 ?
that's an interesting question. As luck would have it I have 2 horses and a full batch of severne and simmer masts. do I have the time and desire to measure is the question. while severne is considered cc I'm betting it's leaning towards the hard top as I know many people that use north masts and are very happy with them in their severne sails even though the heads look looser than stock.
Agree this has killed it for some.. also can't help but notice the people on marketplace selling full quivers of gear with complete mismatch. I often wonder if they would have stuck with it with the correct gear..
we are kinda now stuck in this space where constant curve gets thrown around without referencing that it's a scale. Cc, hard top, flex top they only really provide loose context.... the list above lets people make a choice based on data. I'd rather see those numbers getting publicised.
it absolutely blows my mind that beyond consider the right mast for the sail we should also consider buying masts that are similar in age to the sails for some brands. that this changes from year to year with some brands is not really doing any favours to the consumer. I understand those year to year changes won't really make a huge difference but why do we have to accept less than perfect considering the cost. I think I read that duotone recommended upgrading masts every few years to ensure closest match.
simmer as another example released a new masts for their new carbon sails. knowing what I know that really pissed me off..and yes I use the sx10 but now I'm left wondering but I don't want to buy another mast for one sail.so I get left with, don't buy the carbon sail or don't buy the new bend curve mast or just wonder what the differences are.
Another variable would be the age of the mast and the amount of use its had as masts can lose their flex response over time.
I've noticed that with an older mast which looked great on paper but felt unresponsive and lifeless.
I think brands should be more explicit about mast changes. Maybe give them an iteration number so that we know that a sail from the 2025 range for instance, has been designed on mast iteration X. The best we can do now is buy the sail and mast at the same time.
Anyway, at this point I'd consider sail and mast a set. Another brand's mast is a no for me (even though it might work as mentioned above).
We've got plenty of influencers in our sport now, they should raise awareness and educated folks about how a mast relates to the sail.
Unless going for top gps numbers, go for the best looking (to you) sail. Try a few different things during your first sessions, take notes.
Sometimes a sail will perform better with a mast from a different brand!
Forget anything less than 75% carbon and off you go.
Often times freeride sails are cc anyway across most manufacturers.
Select to expand quoteManuel7 said..
Unless going for top gps numbers, go for the best looking (to you) sail. Try a few different things during your first sessions, take notes.
Sometimes a sail will perform better with a mast from a different brand!
Forget anything less than 75% carbon and off you go.
Often times freeride sails are cc anyway across most manufacturers.
Seriously..your advice is choose a sail that looks good and use any mast.
Select to expand quoteAI.Dave said..
Another variable would be the age of the mast and the amount of use its had as masts can lose their flex response over time.
I've noticed that with an older mast which looked great on paper but felt unresponsive and lifeless.
True. One of the issues when measuring used gear..
this also got me thinking. The standard test involves a 30kg weight. When we downhaul our sail we apply way more tension than 30kg.. each brand must use different tensions when designing. Surely different tensions mean different bend curves.
Select to expand quoteptsf1111 said..
I think brands should be more explicit about mast changes. Maybe give them an iteration number so that we know that a sail from the 2025 range for instance, has been designed on mast iteration X. The best we can do now is buy the sail and mast at the same time.
Anyway, at this point I'd consider sail and mast a set. Another brand's mast is a no for me (even though it might work as mentioned above).
We've got plenty of influencers in our sport now, they should raise awareness and educated folks about how a mast relates to the sail.
Yup. That's my approach too
I'm more sanguine about mixing brands of sails and masts. I've successfully used KA masts with Duotone Warp sails. I've also successfully used KA & Naish masts with North 3Di wave sails.
Select to expand quoteJohn340 said..
I'm more sanguine about mixing brands of sails and masts. I've successfully used KA masts with Duotone Warp sails. I've also successfully used KA & Naish masts with North 3Di wave sails.
I think you got lucky. Going out on a limb here I suspect ka and duotone have very similar numbers. Could prob also use unifiber cc as well but I haven't tested those masts.. Gotta say that after using ka for nearly 10 years before switching to simmer there is no way ka is constant curve because ka has a small amount of flex in the head. Having compared true cc against ka masts the ka masts were better by far which is again another vote for using brand specific masts. Ka has a 13.5 bend curve classification which is not CC. CC is 10-12 ie. severne is CC, older north is CC although either ends of spectrum.
the classifications are
0-6: Hard Top
7-9: Hard Top / Constant Curve
10-12: Constant Curve (CC)
13-15: Constant Curve / Flex Top
16-18: Flex Top
unifiber to their credit have pointed out this system doesn't go as far as is required because you can have 2 masts with very different shapes having the same classification so they came up with fl and fh.
which brings us back to the numbers in the first post. The unifiber system while good is designed to suit a range. Some of us would like a more specific set of data. Publishing the 1/4 and 3/4 numbers gets pretty close.
that said, I'll always choose the brand specific mast as in my experience it trumps everything else. For those less concerned this thread may help them get closer.
Select to expand quoteAUS4 said..
Slake mast made to Duotone specs, does not suit.
Seems there is no consistent duotone spec so what did slake base their spec on. If you know the numbers post them..
Select to expand quoteAUS4 said..
Unifiber compatible mast, not suitable.
Both north and duotone changed bend curves over time. I guess that's the point.
Do sail manufacturers typically commit to a mast bend curve for a certain amount of time? Are you generally safe to mix sails and masts from the same manufacturer a few years apart?
Is it feasible to test mast bend curves at home?
MP
Select to expand quoteMJP68 said..
Do sail manufacturers typically commit to a mast bend curve for a certain amount of time? Are you generally safe to mix sails and masts from the same manufacturer a few years apart?
Is it feasible to test mast bend curves at home?
MP
Some brands are backwards compatible for many years. Some not so much. partly because of significant bend curve changes due to pushing designs forward, employing different designers, pro testers wants etc.
what has happened over time in the industry is that generally bend curves have moved right on the scale towards constant curve flex top. Not to many brands are true constant curve anymore and as has been said already some brands change bend curve within their range depending on length of mast because that provides the best outcome for their designs.
so a few years apart then absolutely go for it if you are talking from say 2020 onwards. If talking from 10 years ago then I would be cautious depending on brand, because not only could the bend curves have changed but there may also be differences in mast diameter. I'm not sure this thread is pushing for changing masts every year more that if you want the best performance from your gear then brand specific masts are the go. For those not wanting to do that or unable to then hopefully the numbers above help get as close as possible.
the big picture is, if you want to take the guesswork out of things then get the mast the sails were designed for..it is always the best choice..
Some of the reasons people say they are happy with off brand masts can be because of the points below
1. They fluked or were informed enough to understand which off brand masts are close enough.
2. They choose a mast with a slightly more flexible top as this gets interpreted as more forgiving.
3. They have never tested brand and off brand side by side.
4. They simply don't care about this stuff.
now I'm certain there are people that strongly disagree with me. Probably less people then the amount of people asking for help for their sails that look weird or feel strange on the water.
Measuring is fraught with issues but very easy to do. I gave up eventually as inaccuracies are way to easy to find in your garage.. 1mm makes a big difference both in flex and length. You can find info online on how to do it.
Select to expand quoteMJP68 said..
Do sail manufacturers typically commit to a mast bend curve for a certain amount of time? Are you generally safe to mix sails and masts from the same manufacturer a few years apart?
Is it feasible to test mast bend curves at home?
MP
The simple answer is yes, but. Daffy and I spent a day testing a lot of different masts looking for specific bend numbers. It's a slow process of setting everything up for each mast but we got our answers in the end. Over the years I've run different brand masts to get a sail that worked for what I was doing. I'm currently running Duotone Sails with Ka/ North and Duotone with results that I like. They may not be what the manufacturer wanted but I'm happy.
Kato, Knowing you've been measuring masts for 20 or so years. can you share the 1/4 - 3/4 numbers?
Select to expand quoteGestalt said..John340 said..
I'm more sanguine about mixing brands of sails and masts. I've successfully used KA masts with Duotone Warp sails. I've also successfully used KA & Naish masts with North 3Di wave sails.
I think you got lucky. Going out on a limb here I suspect ka and duotone have very similar numbers. Could prob also use unifiber cc as well but I haven't tested those masts.. Gotta say that after using ka for nearly 10 years before switching to simmer there is no way ka is constant curve because ka has a small amount of flex in the head. Having compared true cc against ka masts the ka masts were better by far which is again another vote for using brand specific masts. Ka has a 13.5 bend curve classification which is not CC. CC is 10-12 ie. severne is CC, older north is CC although either ends of spectrum.
the classifications are
0-6: Hard Top
7-9: Hard Top / Constant Curve
10-12: Constant Curve (CC)
13-15: Constant Curve / Flex Top
16-18: Flex Top
unifiber to their credit have pointed out this system doesn't go as far as is required because you can have 2 masts with very different shapes having the same classification so they came up with fl and fh.
which brings us back to the numbers in the first post. The unifiber system while good is designed to suit a range. Some of us would like a more specific set of data. Publishing the 1/4 and 3/4 numbers gets pretty close.
that said, I'll always choose the brand specific mast as in my experience it trumps everything else. For those less concerned this thread may help them get closer.
The above photo is my 2020 7.7 warp rigged on a KA 460 100% carbon SDM mast. It rigs and rotates beautifully. I recorded a 2 sec speed of 38 kts on this gear later in the day when the wind increased to 18kts
Select to expand quoteAI.Dave said..
Another variable would be the age of the mast and the amount of use its had as masts can lose their flex response over time.
I've noticed that with an older mast which looked great on paper but felt unresponsive and lifeless.
Excellent point. Masts are cheap as chips now days. Roughly 1/2 the price of a sail. It used to be the other way around. So, I think your advice is good. However, the Made in China masts (nearly all of masts now days from what I've seen), are not as good quality as the older masts that are not made there. So, I like to hang onto old masts.
Also, this is obvious, but I see people do it. If it's a hot summer day, and your mast has been baking in the trailer or left on the ground in the sun, don't rig it up. Put it in shade or dip it in the sea/lake to cool it down first. When it's cooled down, then proceed.
Gestalt. I agree that "same brand/year" strategy is safe one for users that have limited rigging knowledge or CBF.
Select to expand quoteJohn340 said..Gestalt said..John340 said..
I'm more sanguine about mixing brands of sails and masts. I've successfully used KA masts with Duotone Warp sails. I've also successfully used KA & Naish masts with North 3Di wave sails.
I think you got lucky. Going out on a limb here I suspect ka and duotone have very similar numbers. Could prob also use unifiber cc as well but I haven't tested those masts.. Gotta say that after using ka for nearly 10 years before switching to simmer there is no way ka is constant curve because ka has a small amount of flex in the head. Having compared true cc against ka masts the ka masts were better by far which is again another vote for using brand specific masts. Ka has a 13.5 bend curve classification which is not CC. CC is 10-12 ie. severne is CC, older north is CC although either ends of spectrum.
the classifications are
0-6: Hard Top
7-9: Hard Top / Constant Curve
10-12: Constant Curve (CC)
13-15: Constant Curve / Flex Top
16-18: Flex Top
unifiber to their credit have pointed out this system doesn't go as far as is required because you can have 2 masts with very different shapes having the same classification so they came up with fl and fh.
which brings us back to the numbers in the first post. The unifiber system while good is designed to suit a range. Some of us would like a more specific set of data. Publishing the 1/4 and 3/4 numbers gets pretty close.
that said, I'll always choose the brand specific mast as in my experience it trumps everything else. For those less concerned this thread may help them get closer.
The above photo is my 2020 7.7 warp rigged on a KA 460 100% carbon SDM mast. It rigs and rotates beautifully. I recorded a 2 sec speed of 38 kts on this gear later in the day when the wind increased to 18kts
That's great to know, adds real weight to the numbers above.
I suspect less sanguine and more insider knowledge after reading yours and Kato's posts. Would be even better if you guys shared the numbers.
Select to expand quotejn1 said..AI.Dave said..
Another variable would be the age of the mast and the amount of use its had as masts can lose their flex response over time.
I've noticed that with an older mast which looked great on paper but felt unresponsive and lifeless.
Excellent point. Masts are cheap as chips now days. Roughly 1/2 the price of a sail. It used to be the other way around. So, I think your advice is good. However, the Made in China masts (nearly all of masts now days from what I've seen), are not as good quality as the older masts that are not made there. So, I like to hang onto old masts.
Also, this is obvious, but I see people do it. If it's a hot summer day, and your mast has been baking in the trailer or left on the ground in the sun, don't rig it up. Put it in shade or dip it in the sea/lake to cool it down first. When it's cooled down, then proceed.
Gestalt. I agree that "same brand/year" strategy is safe one for users that have limited rigging knowledge or CBF.
Yeah I drill my son about keeping gear in the shade. Worthwhile doing that.
i'll probably get the new simmer mast.. you are spot on that masts are cheaper now and I'm super happy with the feel and build quality of the simmer sx10. The response on the water is great.. booms are expensive.. That may be my next wormhole.. Measuring booms and extensions.. I've got simmer, severne, ka and Fiberspar carbon booms and simmer and severne extensions.
Prob gonna have to measure my masts as I can't find anything about bend curve numbers for simmer although I'll keep digging.
So i'll go out on a limb regards severne.. I think they are ball park 63.5/73.5 or 64/74. That's based on severne confirming many times their masts are cc ie 10-12 and the Peterman data. that's a guess unfortunately. i also believe that there are subtle stiffness differences between their red, blue and g masts. Not a massive issue. it's also most likely the s1 pro were developed on the g masts.. whilst this was the case previously, I'm not sure if it is still the case.
looking at the numbers above the s2 Maui mast is probably a good fit for severne.. is anyone running s2 masts in their severne?
I found another source which has the following. I'll update the list above when i have time but understand this is not from the brand and is older data That may have changed.
ka 63.5/76.5 - note this equals 13. Not 13.5 as stated by brand.
loft sails - 64/76
Select to expand quoteGestalt said..
Prob gonna have to measure my masts as I can't find anything about bend curve numbers for simmer although I'll keep digging.
I would love to make a measuring rig, and characterise my masts. Especially how they drift with age, and when they get permanent bends in them. One day... one day....
Instead of measuring, which can be useful, I'm thinking of doing some experimentation. In our local gang, there's a few different sail brands being used. It'd be fun to swap masts around, sharing experiences with what feels good and bad.
I've got a fair bit of different brand rdm 400 masts laying around, so we could all try the normal mast, then two different brands, just to feel how much it can affect the sail. Who knows we find a golden combo 🤣
Select to expand quoteMeasuring booms and extensions.. I've got simmer, severne, ka and Fiberspar carbon booms and simmer and severne extensions.
Happy to measure (or provide to have measured) my Goya boom and extension.
Select to expand quoteMJP68 said..Measuring booms and extensions.. I've got simmer, severne, ka and Fiberspar carbon booms and simmer and severne extensions.
Happy to measure (or provide to have measured) my Goya boom and extension.
Great.. I'll start a new thread once I figure out what I'm measuring..
in the meantime. This is the reason I run all brand stuff and don't mix and match.when downhaul is +/- 1cm. extension differences are the last thing needed.
Maybe what's being discussed in this thread is not relevant anymore.. some brands are using the same extensions.thought some measurements would show up differences. www.seabreeze.com.au/forums/Windsurfing/Review/Sail-luff-lengths?page=1
same with booms. what are the dimensions describing, inside head outside head etc. I don't know.
That old thread was quite a ride, but if anything it just proves to me how much the industry stuffed up the overarching measurement issue. They said "be precise" but failed to design in the tools that would support that precision.
My brand new Goya extension doesn't remove any of the confusion. It has a fairly obvious gold coloured pin that (I presume) anchors the carbon tube to the plastic pulley housing. Now, you would think that this very visible point would make a great "0" reference point for the bottom of the sail pulley to line up to when rigging.
But does the distance from the top of the collar to that point equal what measurement the extension is currently set to? No. No it does not. That turns out to be an (unmarked) point unevenly between the pin and the top of the plastic collar.
Opportunity missed.
Select to expand quoteMJP68 said..
That old thread was quite a ride, but if anything it just proves to me how much the industry stuffed up the overarching measurement issue. They said "be precise" but failed to design in the tools that would support that precision.
My brand new Goya extension doesn't remove any of the confusion. It has a fairly obvious gold coloured pin that (I presume) anchors the carbon tube to the plastic pulley housing. Now, you would think that this very visible point would make a great "0" reference point for the bottom of the sail pulley to line up to when rigging.
But does the distance from the top of the collar to that point equal what measurement the extension is currently set to? No. No it does not. That turns out to be an (unmarked) point unevenly between the pin and the top of the plastic collar.
Opportunity missed.
Good point, not knowing where you measure from, makes rigging by numbers meaningless. I use the recommended extension length only as a guideline, a first starting point, then adjust final downhaul until I get the sail shape I'm after. If required, I often adjust on the water.
Select to expand quoteMJP68 said..
That old thread was quite a ride, but if anything it just proves to me how much the industry stuffed up the overarching measurement issue. They said "be precise" but failed to design in the tools that would support that precision.
My brand new Goya extension doesn't remove any of the confusion. It has a fairly obvious gold coloured pin that (I presume) anchors the carbon tube to the plastic pulley housing. Now, you would think that this very visible point would make a great "0" reference point for the bottom of the sail pulley to line up to when rigging.
But does the distance from the top of the collar to that point equal what measurement the extension is currently set to? No. No it does not. That turns out to be an (unmarked) point unevenly between the pin and the top of the plastic collar.
Opportunity missed.
Yup. That's why I use simmer extension on my simmer gear and severne extension on the severne gear.. then it just works. I rig to the numbers and I don't need to think about it as I know I have accuracy.
use your Goya extension with Goya components and the rest doesn't matter, just set it to the length required and move on..
