Select to expand quoteMrCranky said..
For example, will a 2013 NP mast be compatible with older (and future) NP sails?
I haven't had any issues with the ones I've used, going from original X9's through to last X9 and now Fx100's (no consistency i my mast collection), they all rig ok, a couple of older sails(RSR Eiii) have benefited a bit from the new masts
It can happen if a company has one main sail designer, and the person is replaced by someone else. I think both Gaastra and Maui Sails switched from hard top masts to a more mainstream bend curve in the last year or two.
Select to expand quoteboardsurfr said..
It can happen if a company has one main sail designer, and the person is replaced by someone else. I think both Gaastra and Maui Sails switched from hard top masts to a more mainstream bend curve in the last year or two.
What is "mainstream"? Constant-curve? I need to buy smaller sails (and mast... and boom). I have the same analysis-paralysis I had buying my first kit (all NP).
Select to expand quoteMrCranky said..boardsurfr said..
It can happen if a company has one main sail designer, and the person is replaced by someone else. I think both Gaastra and Maui Sails switched from hard top masts to a more mainstream bend curve in the last year or two.
What is "mainstream"? Constant-curve? I need to buy smaller sails (and mast... and boom). I have the same analysis-paralysis I had buying my first kit (all NP).
Constant curve masts are masts that are as bendy at the bottom as they are at the top.. Hard top masts are more bendy at the bottom, so if you want a flex top mast just turn your hard top upside down..
That makes sense, right team?
If you can believe the Unifiber Mast Selector Chart over various years it does show that some maufacturers have changed there masts characteristics. Example comparing 2011 and 2014 charts
- Ezzy is now slightly more flex top
- Loft is now slightly more flex top
- Maui Sails is now now in the Constant Curve range
- NP same
www.unifiber.net/masts-selector
www.unifiber.net/2014/mast-selector
Select to expand quotebarn said..MrCranky said..boardsurfr said..
It can happen if a company has one main sail designer, and the person is replaced by someone else. I think both Gaastra and Maui Sails switched from hard top masts to a more mainstream bend curve in the last year or two.
What is "mainstream"? Constant-curve? I need to buy smaller sails (and mast... and boom). I have the same analysis-paralysis I had buying my first kit (all NP).
Constant curve masts are masts that are as bendy at the bottom as they are at the top.. Hard top masts are more bendy at the bottom, so if you want a flex top mast just turn your hard top upside down..
That makes sense, right team?
Ahhh...... not quite. The term 'Constant Curve' is quite misleading, as is the term 'Hard Top'. Almost all masts bend more at the top half than the bottom half.
Masts are classified by the difference in bend curve between the top half and the bottom when they are supported near the tip and base and a 30KG weight is suspended from the middle. The difference measured is expressed as a % difference. According to the original classification, 'Constant Curve' masts are those with a difference of between the top and bottom of between 10% and 12%, but the classification tend to be a bit broader than that in practice as 'Hard Top' is 6% and less and 'Flex Top' is 16% and greater.
There are very few sails today that call for 6% curve masts. Most of the so called 'Hard Top' sails are designed for masts around 8% to 10%.
Sails that call for 'Flex Top' masts in the 16% to 18% range are reasonably common, but I would say from my observations that most sails today are designed around masts in the 12% to 15% range. Masts in this range seem to suit the majority of sails expect those few designed for 'Hard Top' masts.
www.peterman.dk/mast-imcs-formulas.htm
That's not at all enough ...
First one should consider the way flex changes along the mast length. Some mast show a gradual change (typically Maui Sails), others show an abrupt change at mid length (typically Neil Pryde); and this seems to count more than just classification. I mean: a Maui Sails TR- on a CC or even FT mast with a gradual bend change will be OK, same sail will not work nicely on a CC with an abrupt bend change.
Second, the ususal IMCS test will not sy it all. In '12 Maui Sails changed their 460 100% race mast. The new one had the same IMCS bend as the old one; but had a smaller diameter top that changed it all in real life. The point is that masts are charged in a totally different way than that the IMCS system does: loaded along their length, instead of loaded with a weight put at 90° re. their length at center point. The mast rigged in a sail flexes in a different way than the same mast on an IMCS test bench.
To the end of model year 2005, NP masts were CC. The earliest written NP reference I could find is the following:
NP 2002 Product Book, p12
The X3 carbon mast is a performance cross over mast with a bend curve suitable for any NeilPryde sails and compatible with most brands on the market (writer’s emphasis added).
Beginning model year 2006, NP introduced the Progressive Flex concept as described here:
NP 2006 Product Book, p71 Over the years NeilPryde has developed the “Progressive Flex” bend curveto truly maximise sail performance. …………It combines a stiffer bottom section with a lightweight and responsive top section. A stiffer bottom section is required for draft stability and power, while the lightweight and responsive top section provides release in the head of sail for control
Beginning model year 2013, NP introduced a mast system with 2 bend curves as described here:
NP 2013 Product Book, p45 The standout feature of NeilPryde masts is the unique flex and bend curve. Our shorter masts are close to ‘flex-top curve’ while longer masts are closer to ‘constant curve’ - this is why we call it the Progressive Flex and Bend Curve.
The writer asks “define a short mast and define a long mast”. For example, in his quiver of 370, 390, 400, 430, 460 and 490 masts, a long mast could be a 400 and up.
The writer comments on the 2 bend curves: On bigger masts (when fitted to Freeride/Freerace and Race sails?), the move back to CC contradicts the explanation in the 2006 book, “stiffer bottom section for draft stability”, where draft stability is on these types of sails.
In answer to the OP’s question “For example, will a 2013 NP mast be compatible with older (and future) NP sails”, the answer is a resounding DEFINITELY MAYBE, the key word being “compatible”. However, if the OP asks “Can I use any NP model year mast in any NP model year sail, the answer is YES.
Readers: feel free to analyse and comment on the above, ad finitum.
Maybe the difference between mast of the same brand with the same bend curve is coming from the way it is built that impact the way it react with the sail .
The way is is built, the construction process can also give a more regular product : mast are more simillar the original design, there is less difference between each mast product ????
Thanks for the tips. So what's the "default" sail/mast brand these days? Severne? 'Cause it's Aussie like JP?
Select to expand quoteMrCranky said..
Thanks for the tips. So what's the "default" sail/mast brand these days? Severne? 'Cause it's Aussie like JP?
KA Sails Australia of course! 
All KA sails rig fine on CC through slightly flex top. Default is 13.5% bend curve.
Magnum35 makes a good point though. The way the sail is designed and built will make a difference. Some designs are noticeably more tolerant of a wider range of mast curves because of the combination of the type of Luff curve and seam shaping built into the sail.
When fine tuning my Slalom/Speed sails I sometimes try slightly different masts for certain conditions, but the differences are usually very subtle. At Luderitz Last year, I watched AA change the mast in his sail 3 times after each successive run until he seemed satisfied. They all looked the same to me. I wish i was able to tell that fine a difference! 
Select to expand quotesailquik said..
AA change the mast in his sail 3 times after each successive run until he seemed satisfied. They all looked the same to me. I wish i was able to tell that fine a difference!
I think it sums it up pretty well, we (as average sailors) wont be able to feel the difference of a different mast in a sail. Best to stick to the same mast/sail brand.
Select to expand quoteRob11 said..sailquik said..
AA change the mast in his sail 3 times after each successive run until he seemed satisfied. They all looked the same to me. I wish i was able to tell that fine a difference!
I think it sums it up pretty well, we (as average sailors) wont be able to feel the difference of a different mast in a sail. Best to stick to the same mast/sail brand.
Yeah I figure that I can't tell the difference... except overpowered/underpowered. What about sturdiness, weight... price? How do brands compare in this regard?
Select to expand quoteRob11 said..
sailquik said..
AA change the mast in his sail 3 times after each successive run until he seemed satisfied. They all looked the same to me. I wish i was able to tell that fine a difference!
I think it sums it up pretty well, we (as average sailors) wont be able to feel the difference of a different mast in a sail. Best to stick to the same mast/sail brand.
I disagree, stick a 3 or 4 y/o Maui Sails mast in a NP wavesail and see how you fare. You will feel it, would be horrible 
I saw A² do it here before the pwa event, two tacks, check the gps, try another mast (same brand/year) do it again...
All afternoon....
All his masts have red tape with notes on them, as to with what sail and in which conditions....
talk about perfectionism !
"Do mast manufacturers ever change mast curves"
Definite YES.
When Barry Spanier was with NP - many moons ago - there were hard top masts at NP
After Barry left NP they became and stayed FLEX top.
MauiSails, Gaastra and Severne were always the HARD top masts.
Just recently MauiSails switched from HARD top to CC (Barry Spanier is here now)
if one is using race sails, it only makes sense to use the manufacturer's masts of the same year
for camber rotation, etc
when i have tried or seen the inappropriate mast in a sail, it seemed to show most in the leech section
or unable to downhaul enough to get battens around/near middle of mast
when it is close enough, us mere mortals or average joe windsurfers are in it for the FUN and TOW and may not even notice the difference
my son recently moved to Sydney and tells me there are more surfers than windsurfers
WTH - better not be just mast issues 
here is a KA sail with a NP mast from earlier discussions on this forum:
Select to expand quoteRob11 said..sailquik said..
AA change the mast in his sail 3 times after each successive run until he seemed satisfied. They all looked the same to me. I wish i was able to tell that fine a difference!
I think it sums it up pretty well, we (as average sailors) wont be able to feel the difference of a different mast in a sail. Best to stick to the same mast/sail brand.
I didn't say I can't tell the difference between different masts at all. I can, and that's why I sometimes change them. But the degree of difference A2 was looking for seemed to be at another level altogether. 
Select to expand quoteMark _australia said..
^^^ doesn't say much about manufacturing consistency......
I once read in a British windsurfing magazine about the consistency of masts. Their findings were masts that should be the same in that they are the same product, same year, production run, size and everything else, are different. No two masts are exactly the same as each other.
Moby I have that article and they also found that some masts worked better then the recommended Sailmakers own brand. Not suggesting that you do that unless you had access to a lot of masts and had time to tune and test.
That Boards article was one of the best bits of Windsurfing equipment review I have seen. It investigated a lot of aspects and had a lot of good data analysis. It was not perfect, but the best so far, (although the English language media is very sparse on this sort of testing and if they do it at all, it is almost always very shallow).
I have done a lot of IMCS mast testing over the years and it is pretty obvious that there has been a surprising amount of variation, mast to mast, from some manufacturers.
I say 'has been' because more are now actually testing every mast before it leaves the factory to make sure they are within specs (there will always be small tolerances),
For example, when KA Sails changed mast manufacturer a couple of years ago, one of the conditions is that each mast is tested and it's specs recorded, and it must be within tolerances to be shipped. I am sure more manufacturers are now doing the same.
And as geoITA says, the IMCS method is not perfect, but it is still extremely useful in my experience.
However, I have found exceptions. One was a popular brand of RDM mast that tested to the same base IMCS specs as another but rigged and sailed very differently. Further investigation revealed it was one of those that had more of its flex in the middle near the boom and a less 'even' bend. I didn't have access to enough examples of that particular mast to certain if it was an exception or a general characteristic of the brand, but anecdotal evidence suggests the latter.
Why a 3okg weight ? Surely this does not replicate the force/downhaul(race sails) required to get a mast in a rigged state. Maybe I am just getting weaker in old age.
I once had a beach discussion with a visiting pro about the Avanti Cst made masts and asked that it must be a good thing to have consistent manufactured masts. He replied, that they preferred the variations in masts for sail tuning.
So which masts are used to develop sails, the R and D team sailors best masts or an off the rack mast ?
I can only speculate that when the test was first developed in the '80's, the developer decided that the amount of deflection 30KG gave was about the same as the deflection of a rigged mast. Intuitively, I would say that is still pretty close with many sails.
Another way to test is to tension the sail from tip to base with measured force. Problem with that is the luff curve on modern sails does not tension a mast that way either. At a certain point in the downhaul, the top of the mast and the luff curve pretty much match curves and then the tension points change.
If you have lots of time and a curious mind, it could be fun trying to work out a new relevant test though..... 
Select to expand quotecol5555 said..
Why a 3okg weight ? Surely this does not replicate the force/downhaul(race sails) required to get a mast in a rigged state. Maybe I am just getting weaker in old age.
I once had a beach discussion with a visiting pro about the Avanti Cst made masts and asked that it must be a good thing to have consistent manufactured masts. He replied, that they preferred the variations in masts for sail tuning.
So which masts are used to develop sails, the R and D team sailors best masts or an off the rack mast ?
It is irrelevant what the weight is, as it measures the deflection at 25%, 50% and 75% points along the length. It is one mast relative to another so you could use 50kg if you wanted.
It was WAY better than the previous MCS that was near on useless, but as a new improvement we'd love to see bend curve also. 430 /21 / 14% would be great to see!!!!
