Carbon Fibre Tube for BR Mainmast

[retired2sail]

Laying up my BR17 which has a carbon fibre mainmast, I found a problem!  It looks like the mast has leaked somewhere and water has got into the tube.  It looks like the wooded bungs at each end of the mast have swollen and split the tube lengthways.  At the bottom end the split is about 350mm long.  The split is shorter at the top.  So this raises a whole lot of questions:
1) Are the carbon tubes repairable?  If so, how?
2) If they are not repairable I'd like to make a new mast, reusing the fittings off the old one on a new tube.  Can anyone comment on how easy this would be and provide a build procedure?
3) If I can replace just the carbon fibre tube, where would I buy the material and what specification should I be looking for?  A quick look on the internet doesn't throw up anything obvious.
4) Is it possible to use an aluminium tube if I can't get hold of carbon?  If so, the same questions - who can supply the tube, what spec and a build procedure?
Any help and advice gratefully received!.....

[Graham W]

Chris,

It might be worth having a word with these people http://www.carbonology.com/carbonology-repair-service-c-147.html or these http://carbonfibrerepair.com.  Neither of them are anwhere near Cornwall!

[Peter Cockerton]

Have you considered a stainless steel boot for the bottom of the mast, you could fill the boot with a liquid, perhaps epoxy resin and put the mast into the snug fitting boot. I did this on my wood mast on my BR20 to repair a nasty split which developed from the base some 6 inches up the mast. The fittings for the securing pin on the tabernacle are now screwed through the SS boot into the mast. One additional benefit is the SS tabernacle fitting does not take slithers of wood of the mast now when raising the mast when it's not quite vertical when entering the mouth of the tabernacle.

Peter

[Michael Rogers]

That sounds like rotten 'luck', Chris.

It would be worth having a word with Matt as well. He'd probably like to know, and it might have happened before.

I'm pretty sure splits in CF tube can be fixed, if only by wrapping with CF tape, suitably adhesive -d. It may not be comparable, but musical instrument repairers can fix splits in wooden woodwind instruments with wrappings of some sort of CF tape which is very thin and extremely strong.

I've got a CF mast with wooden bungs in each end. I hope to sail tomorrow, and I shall make a VERY careful inspection! Best of luck. At least you've got the lay up season to sort it for next year. Perhaps in due course you could give us a report on how you got on?

Michael R  (Trouper12 'Cavatina')

[Rob Johnstone]

I managed to split the lower section of the CF mast on Vagabond by dropping it on one of the cabin top winches when losing control whilst lowering the mast. I ended up with a split of about 4 feet, and a bent section of the sail track. Although my insurance company told me they would be able to find and expert to repair the split, I took the easier route of having Swallow Yachts replace the bottom section of the mast and track. I'm picking the boat up next week.

When the split occurred it was obvious that there has a half pint or so of water within the mast but (as far as I know) there had been no deterioration of the wooden plugs. I spoke with Paul (Swallow production manager) and seem to think that Swallow now allow for a small drain hole at the base of the mast to try to reduce the problem.

Rob J

[retired2sail]

Thanks for the replies.  I've also taken Michael's advice and contacted Matt.  It is interesting that Swallow now put drain holes in their hollow masts and that Rob Johnstone found water in his.  I was cleaning down my tender today which is a BIC 245.  This is a hollow plastic dinghy and it had a fair bit of fresh water in the cavity and no obvious holes.  I showed it to the owner of the place where I store my boat.  He sells kayaks which have a similar construction. He says it is common to find fresh water in them and that it is condensation.  So presumably the dinghies, kayaks and carbon fibre masts all "breathe" somehow, drawing in humid air - hence the masts and dinghies need drain holes!  By BIC boat is fitted with a small drain for the cavity.

Based on your replies and Matt's I'm hopeful that I can sort it out over the winter.

Chris

[Matt Newland]

Hello all,
Thanks for your comments.
The mast is totally repairable, as Michael says, by wrapping with tape (glass fibre tape is perfect) and epoxy. The wooden bungs at the end are vulnerable if any water gets into the mast, (which on a BR mast it shouldnt). They should be thoroughly saturated with epoxy resin where they go into the tube to prevent any swelling, but obviously in your case they have still swollen enough to split the carbon.
I will email you with specific details of the fix, but you should be able to reuse all components, and the fix will make your mast stronger than it was. For those not familiar with our carbon masts, around 90% of the fibres run up and down the mast, its only the last outer layers that are wound around it.
New boats use delrin bungs which cant swell no matter how much moisture.
Matt