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..

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.

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.

Manuel7 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.

ptsf1111 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

Slake mast made to Duotone specs, does not suit.

Unifiber compatible mast, not suitable.

AUS4 said..
Unifiber compatible mast, not suitable.

Both north and duotone changed bend curves over time. I guess that's the point.

MJP68 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.

Kato, Knowing you've been measuring masts for 20 or so years. can you share the 1/4 - 3/4 numbers?

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.

jn1 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?

Gestalt 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....

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.

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.

MJP68 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..