Looks dodgy to me..

I'd be thinking along the lines of putting the top half on, but not all the way, and then having someone bend it while you look into the suspect area (wearing glasses of course ;-) if it moves, it's stuffed.

The three exploded NP's I've seen first hand have failed further down, around the bottom of the ferrule insert, so hopefully it's just the bonding glue.. That said - you are left with the question of why the bonding glue has come under stress, and what else has moved from where it's supposed to be to cause that?

The thinner inside part is just glued in the outer tube, so a crack is not a major big deal compared toa crack in the mast tube itself. For example, a crack anywhere else that big would be guaranteed to explode very soon if used.

I would glue it with a thin to medium CA from a model shop (superglue that is designed to be used when the two surfaces are not touching, or else epoxy it and keep adding little bits as it soaks down into the crack. Should be good for a while longer (cos they are glued in with epocy anyway!!) but I would not sail miles offshore or alone etc.

Thanks for the advice and links (very interesting articles on those links on mast construction/flaws). Will try the "555 bend test" with the top just slightly out, having someone bend the rig whilst I see if the crack moves / opens up at all. It is an old X6 but would like to keep it going if i can.

I was thinking (as suggested in one of forum link replies) that maybe i could get a section of a busted rdm mast and maybe glue inside the ferrule for the length of the ferrule (+4") (if I can find the right diameter). From what I can see there is no problem with the mast elsewhere below the ferrule or bottom of the top section, apart from some general cam wear. Anyone have any bits/sections of an old busted rdm?

Thanks Garry, will contact them and post their reply.

Tony C,

I also talked to Reg at Windsurfing Perth prior to contacting NP about the cracks and he said he knew of people who had been using their X6 masts with the same hairline cracks below the ferrule for a number of years without any failures. Maybe worth showing him your mast with the cracked ferrule and get his opinion as well.

Regarding sleeving a section of an rdm mast inside the ferrule, I suspect that if you did this then you may strengthen the ferrule area considerably but this may create two weak points, one at the bottom of the sleeve and one at the top where the greatly increased ferrule wall thickness meets the normal tubular wall thickness.

With respect to others who have given their advice re X6 masts, it could be misleading to believe that the ferrules on all X6 masts are actually glued in to the bottom section based on what Peter Bijl of NP said in his reply to my question:

This is a mast with an integrated ferrule design, for that reason there needs to be some build up for the top part of the mast to saddle on.

Correct me if I'm wrong but his comment indicates that the ferrule is actually an extension (or continuation) of the mast bottom section where it reduces in diameter to sleeve into the mast top section, hence the build up of material below the ferrule. I've heard that recent builds of X6 std dia masts don't have the same problem with hairline cracks as earlier X6 masts due to different ferrule design, though not sure how X6 masts prior to 07 were built for that matter.

How old is your X6 Tony?

Shame it's got an integrated ferrule! A number of years ago, I busted a fiberspar 30% carbon mast clean at the join and luckily found an identical bottom section which had snapped off around boom level. I managed to get the remains of the broken ferrule out without damaging the inside of the mast too much and also removed the good ferrule intact. Glued the good ferrule into the good bottom section and got at least another 2 years out of the mast!