Hi all,
After alot of consideration i bought a new Powerex RDM 400, also have a powerex 430. I have a basic understanding of mast bend curve / flex, IMCS value's.
I've only been windsurfin for a couple of years and are no expert.
The question i put forward and hope for sum informed educated answears is that we get told by sail manufactures, websites, this forum, magazine articles etc that a certain sail MUST have their mast that that sail was designed for or the sail wont perform or set correctly etc etc.
If you use a north sail you gotta have at least their gold mast but reccomend platinum, severne gotta use the redline but can use blueline.
I can get my head around all this, Use the sail/mast combo that they were designed for/together by the sail designers. Makes perfect sense.. No worries..
So how do the other mast manufactures fit into this, Powerex, Amex, Pro Limit, Sunshine etc.
I use Powerex mast with Tush sails, My mate uses Powerex with KA, the other Powerex with NP, another sailor uses Severne mast and a North sail. Unlike me these guys are very experianced. If Powerex, Amex, etc masts are universal whats with all this same mast/sail carry on from the sail companies.
If you listened to and agree with what the sail companies say about all this than surely powerex, amex etc wouldn't exist.
How many Powerex mast are out their being used by us guys??
So guy's, educate me and others iam sure about all this.
Thanx. 
Maybe Ben could comment. 
hi stone,
i use mainly powerex masts also. there has been a lot of talk about masts on this forum so i am sure some searches will provide the goods.
in short,
a sail is typically designed to suit a masts bend characteristics. and all masts across the board have different bend characteristics. even masts with the same stickers on them can be different between individual units.
so in short, find the mast with the right bend characteristic for a particular sail and it will work.
what confuses things is that some sails are top flex, some constant curve, some bottom flex and some a combination of the above.
some sail manufacturers like KA for eg publish the percentage their sails are designed for. most don't though.
this site www.peterman.dk/mast-imcs-comments.htm has a lot of spec results from testing but as i said above. 2 masts from the same manufacturer can have different actuall bends. that said though they will be close to each other.
typically brands like neil pryde, north and maui sail require non constant curve masts and the majority of the rest sit between flex and constant curve or there abouts.
it is always the best to buy a mast from the same brand as the sail. the other option is to buy the mast from another manufacturer, (like powerex etc) that has the same bend characteristics.
edit*** so not bogus with certain mast/sail combos and bogus for others. 
also wanted to add that some sails will suit a wider variety of mast shapes and still work well while other sails are more mast specific. comes down to luff shape.
Hi Stone , No it is not Bogus. Sail designers enter certain mast bend figures into the design software and the luff curves are designed around these figures. The sails will perform to their optimum on the correct mast.
However the impact of an incorrect mast varies greatly depending on the size and type of sail. Small wave sails for example which have small amounts of luff curve are much more tolerant of mast curve variations as you are not bending the mast enough for it to be hugely effecting the leech twist. They will perform adequately on a greater range of masts. Large race sails like Formula sails have high amounts of luff curve and are very mast specific.Youare bending the mast alot more and the differences in mast bend curves is far more evident. They will perform badly on a mast that is outside the design range of curve as the shape and leech twist will be impacted.
So if your freinds are rigging small wave sails in the combinations you describe they are most likely OK ( although Powerex on NP is pretty dodgy) . I can guarantee they would be better on the correct mast.
If they rigged a 10.7 Neil Pryde race sail on a Maui sails mast for example it would be a disaster, not work at all.
As a general rule always rig a sail on a mast that is close to the recommended IMCS mast curve percentage. Most brands don't publish that figure so email them and find out. There is generally a "non brand " alternative that will be close to the correct curve.
I hope I have shed some light on the subject.
I find a massive difference.......late model (after 2005) NP wave sails rig so badly on an Ezzy (No Limitz) RDM that they are almost unusable and the mid leech flaps so much it is destroying itself. I was pretty sure Powerex RDM's were similar to the No Limitz RDM's so I'd like to see how those NP's are working.
2010 alpha and firefly i've tried works equally good with powerex 85% rdm, as the x9 skinny
with either mast you can even downhaul the bejeesus out of it and panels don't flutter themselves to disintegration, unlike earlier np wave sails - as you stated
Wow ..... NP must have gone back to a slightly more reasonable curve or something? It was quite obvious that 2004or5 to 2008 was a bit weird .... I had an 03 Zone that was magic on an Ezzy skinny and a 2008 Zone would not even look like a sail when rigged on it
So what would be a smart/reasonable strategy if you were windsurfing on a budget? Clearly it will get very expensive if you need to get a new mast whenever you get a new sail. Particularly so if (like me) you are considering transitioning from a complete quiver that is a few years old onto newer stuff, but can only do it one sail at a time.
not that ive seen a properly riged 5m naish force before but mine seems to rig fine on a 400 sailworks lipstick .... ive heard that stiffness of ya mast plays a bit part in how the sail sets 2? what will a stiffer mast do that a soft mast wont?
Mark , the specifications I have seen recently put the NP Combat RDM at 15% ish and the Ezzy RDM at 14%ish. This is just data I have seen published on various forums ect so please don't take it as gospel.
If that is the case then there is not a huge difference in curve, certainly not as much as there used to be when the Prydes were more like 17% curve.
food for thought.
I have had both Tushy 75% SDM and NP x6's these two mast are the same and either rigged exactly the same in each others sails.
IMHO the Tushy 75%freewave is a better mast.
i have rigged the x6's in Tushy rocks and they were fine.
I'm even using a Tushy 75% in a RS Slalom and RS racing and its looks and sails identical to the recomended X6.
I sold my Tushy 490 75% to a fellow who uses it in a Severn Code red 8.3m with good results.
I hope this is some help. I think a safe bet could be a powerex or tushy for masts in a mixed quiver of sails
the only way to find out is rig them and see.
basically you need to try the combo on ur sail before you buy the mast, if the brands are a miss-match.
sometimes it works, sometimes it doesnt. its a case by case situation.
As Bender mentioned, I also use a tushingham 490 100% mast with both my 8.8 (09)& 7.7(07?) Code Reds and they work beautifully. In fact the recommended mast for the 7.7 is a 460 Severne redline which doesn't rig nearly as well as the 490 Tushingham - go figure. Maybe I just got lucky with the mismatch.
Tush is very similar to Pryde (tip flex) ..... My 2004 Search sets beautiful on a 30% Tush SDM
But maybe not so much now that Pryde seem to have gone for a more "middle of the road" bend charateristic.
Nick, softer and siffer is less important than bend curve.
If you use stiffer mast of the same bend curve it will just need more downhaul to achieve the "right" twist, and it will not deflect as much in gusts, making it better for heavy guys.
Eg: I have a 5.2 with 428 luff and recommended mast is a 400 (28cm extn). I prefer it on a 430 (same brand and model mast) with nil extn as I am heavy at 95kg.
That same sail, for down the line sailing where you want it to depower nicely, I'd bet any sailor of 60 - 80kg would much prefer it on the 400 with lots of extension
Most things will work however, unless you are a professional who can test against people you sail with everyday or can easily tell fine differences and have access to many different masts then go for it- but that is not buying 1 random mast and hoping for the best.
Simply if you want the performance you paid for from your sail then match it to the correct mast 
I would 100% agree with using the same brand sail and mast combo, powerex are a good mast, strong durable and suit a large range of sails, i have used them on the Sailworks sails and Severne, but the sails realy come to life, rig way better, respond better and basically feel the way they are ment to on the proper mast..
The best advice i could give to people who are just starting out is to buy find a brand of sail you like to use, try to make all your sails the same brand, even better style and year, and buy the best mast you can afford from that company that the sails are design to run, it doesn't have to be top of the range mast but it should still rig perfect...
Masts are something you can use for a good few years and it gets used every time your sailing.. and you shouldn't need to update your mast everytime you update your sails.. if you stay with the same brand that is..
Gaastra Manic Neil Pryde X3 combo 
Yoyo told me why it looked like crap. It now rigs sweet on one of Ben's masts 
^ unfortunately we've all been there at some time. but once using the right mast/sail combo it is unlikely we will go back.
I have an '08 6.2m2 Blade, and '07 5.7m2 and 5.3m2 Blades.
All rig on a 430 RDM. I have a '08 PWX 85%RDM, and also a '09 Maui Sails 100% RDM.
The Peterman site as well as other sites state the ideal mast, a Severne Redline, is a stifftop @ 9.8 curve.
The Powerex is a 13. The Maui Sails is a 9.1.
I think the Powerex looks better in my sails, especially in the '07s. I think the whole leech is too loose with the Triana made MS mast.
Since, I have not even seen a Severne Redline RDM in my neck of the woods (USA), I have no way of knowing for sure.
I recently talked with Derek Rjiff of Windsport, who told me Severne changed from a Powerex to a more stifftop mast at some point, but he was not sure when.
I am confused as well.
from what i've read from others and my own experience, i reckon the the powerex skinny 85% has been well proven to be a great all round, suit just about everything, and durable, kinda mast. i'd definitely get another
