Why not use the recommended mast firts? Is is not all in the IMCS allone. North need more topfelx masts and it may be that you have a similar imcs mast but one with less topflex or with a stiffer bottom…. Overall it is the same imcs as reccomended but the curvature is probably not the same as in the recommended mast, my guess.
So my idea would be first to try the recommended mast before doiing something that is out of the box.

Good luck and let us know here what you find out.

Even if I know you don’t use North windsurfing sails, I contact you about a Warp issue for a simple advice.

I’ve purchased a second hand 2006 North 9.0 slalom WARP and I have rigged it with a compatible 520 / IMCS 32 mast.

I’ve noticed this sails is very physical and from recent races I came out really exhausted !

I regularly use North formula and free-race sails with their recommended masts and I valued NS sails for their soft feeling but I feel this sail (9.0) is really hard to drive & control when wind rises.

I wonder if this depends on using a compatible (maybe stiffer) mast than original 520 North (anyway, always IMCS 32).

What do you think if instead of using recommended 520 / IMCS 32 mast I will use a softer 490 mast (or a mix of 520 bottom and 490 top) ??

Thank you in advance for any help.

Regards.

The workmanship that goes into a carbon bike frame (even the work that goes into carbon drink bottle holders) is quite astonishing.

But I guess you can have that level of quality when you expect to sell 500,000 units of drink holders instead of maybe 1000-2000 masts. Bike “parts” are cheap, but framesets are still not (retail around US$4500 for my bike), so I guess all products still have to pay for the R&D that goes into their products and their teamrider’s salaries.

I still get a lot of emails from sailors here in Australia, asking what brand of sails they should try this year and whether or not the masts will break. What can you tell them? Every brand is in the same situation (almost)… I have trouble selling second hand sails because I don’t want to sell the masts with them; you need to have so many spare masts to do the tour these days :(

…”how the heck would I fit this pre-bent mast into my car” ??

:)

Below is an extract from the Formula Windsurfing Class Rules which prohibits pre-bent masts:

“F.1 MAST
F.1.1 CONSTRUCTION
(a) The spar at any cross section normal to the mast axis shall be circular and of uniform thickness.
(b) Pre-bent masts are prohibited.
(c) The bending curve of the mast shall be equal in all directions”

The design of modern FW sails with the wide luff sleeve and cambers requires high downhaul tension for a number of reasons including:
- improving the stability of the front section of the sail to resist backwinding and also to lock the draft in position making the large sail friendly to use in high winds;
- tensions the sail fabric along the leech;
- opens the upper leech section which helps to reduce the vortex or induced drag near the head of the sail;
- keeps the luff sleeve smooth when the mast flexes

Just my 2 cents

what do you think?

I was told it’s not a common problem, however on the odd mast, even at times on the odd batch of masts! Problems sometimes arise. The general census of opinion is the resin or sealant used between the collar and the mast is either applied too heavily or too sparsely, “ultimately unevenly”. Needless to say that unevenness of glue or resin results in unequal stresses being sustained by the thin alloy collar as well as allowing direct contact between the alloy and carbon which can result in corrosion and weakening of the collar.
This corrosion can not possibly be what happened with my mast as it was only used 6 times. As Ola H said on the star-board forum, it was more a case of simple geometry in my case.

I would be interested if some of the guys who have first hand experience in the designing and manufacture of masts could share their knowledge with us on this issue.

My Singapore based North supplier heard my case and got onto North head office in a flash. Had confirmation of a replacement mast in less than a day! Lucky me huh? oh BTW, Windsurf and snow in Sydney do stock most North kit. The high end race stuff is not imported to OZ as stock, but can be specially ordered i’m told.

Thanks for the wicked site,
am learning so much here
@ CARBONSUGAR keep it up.
Loads of the Greek crew are reading your stuff too!

There’s a post on the Star-Board forum with some guys having a similar problem with the Severne masts (although their collar appears to be aluminium rather than plastic) - check it out:

http://www.star-board.com/forum/showthread.php?t=3344

Otherwise, I’d be taking it to your dealer to see what they say. Is there even a North dealer here in Aus??

Quick question about the collar that wraps the top of the bottom piece of the mast. My new North Platinum 460 has started to split at the bottom edge of the collar after only 6 sessions. Unlike the severne Alloy collars, mine looks to be plastic.

Thanks,
Jason