tpi carbon masthead repairs.

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phildowney
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Joined: Sat Mar 14, 2009 3:59 pm
Location: Southampton
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tpi carbon masthead repairs.

Post by phildowney »

Hi climbed my mast today and found severe corrosion on the masthead fitting has split the mast tube due to the expansion. has anyone encountered this before and effected a repair, and is there a different or better way to arrange the masthead fittings that anyone has on their boat?

she is a 1981 freedom 35, with black carbon masts imported from tpi
Owner of Kusi, UK F35 Cat ketch
Southampton UK

andygc
Posts: 92
Joined: Sun Jul 31, 2016 4:33 pm

Re: tpi carbon masthead repairs.

Post by andygc »

I had a similar problem with one of my masts - on a 1981 FR30 CK. The aluminium plug had split the top of the mast on one side - a very neat split running round the mast, almost like a knife cut. The casting extends down the mast beyond the split and was not at all loose. The boatyard's laminating expert removed the broken piece of carbon fibre laminate and then stripped the paint off the casting. Then the metal was acid etched and painted with several coats of an epoxy paint. He then rebuilt the missing section and finished with white paint. I can't give you full details of what he did now as he is off for the yard's Christmas break. The mast was painted white many years ago - which seems to me a very good idea as it reduces UV damage to the laminate.

The other mast (mainmast) is a replacement (no idea when, other than it was fitted by the first owner before 1999) which avoids the problem - the crane is a moulding with an inverted U cross section. Unlike the mizzen it reaches aft with no forward extension - the only thing on the front of the mast is an eyeplate for a burgee halyard. The masthead lights are screwed straight into the top of the mast. I can't post photos until after the New Year as the boat is in the workshop.

PS. I hope your mast comes out easier than mine did!
Sold for health reasons :(

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phildowney
Posts: 90
Joined: Sat Mar 14, 2009 3:59 pm
Location: Southampton
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Re: tpi carbon masthead repairs.

Post by phildowney »

Thanks, I'd be interested in any more details and photos you have, especially of the alternative masthead construction as this being the mizzen, a fixed rather than rotating masthead construction is appealing.
Owner of Kusi, UK F35 Cat ketch
Southampton UK

andygc
Posts: 92
Joined: Sun Jul 31, 2016 4:33 pm

Re: tpi carbon masthead repairs.

Post by andygc »

I must apologise. The boatyard wanted to move the boat as soon as they reopened on 3 January and I was pressed to get the masts rigged so they could be stepped while the crane was in the yard. In the rush I completely forgot to take photos. Here's two taken when the boat arrived in the yard.
Masthead2.jpg
Masthead2.jpg (144.22 KiB) Viewed 4441 times
The crack in mine was on the other side (sorry) in line with the bottom edge of the crane and running straight around the circumference. (Note that the 30 doesn't have a swivel in the crane)
Masthead1.jpg
Masthead1.jpg (101.62 KiB) Viewed 4441 times
You can see the moulded crane on the mainmast pretty clearly, pointing downwards.

The repair to the mizzen:
Cut away the broken carbon fibre laminate from the crack to the top of the crane. The corrosion was much less than expected. The first thought had been to pull out the crane plug to rebuild the top of the mast, but the plug extended well down the mast and was wedged in by resin - it was solid, and so not in need of any re-fixing.
Remove corrosion.
Acid etch to stop corrosion in pits.
3 coats of Hempel light primer.
Build up area of missing laminate with carbon fibre and epoxy laminations.
Fill and fair (very little needed).
Finish with 2-pack epoxy paint.

The mainmast crane moulding is laminated about 7-8mm thick. I don't know if it is carbon fibre or glass - it's protected by a white flow coat. I think the mast was made by Carbospars, but I think they have ceased trading.

I hope that's helpful.
Sold for health reasons :(

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