Mast Refit (part 1)

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patentnick
Posts: 57
Joined: Tue Oct 23, 2012 11:51 am

Mast Refit (part 1)

Post by patentnick » Thu Mar 01, 2018 1:49 pm

Hi to all:

When I first bought Moments of Clarity 17 years ago, the first job I did was to replace all standing and running rigging. I'd been thinking of replacing all the wires once again for several years now and, this year, with the boat out of the water for antifouling, new cutlass bearing and Volvo stern gland, I decided it was time to lower the mast. With the mast down--and secured on five oil drums--I removed all the chainplates and backing plates, the galvanised beams and the deck eye bolts. It's a testament to the original quality of all metal components that they required no attention, other than removing the old caulking material and polishing. There were just a couple of spots of surface rust on the galvanised beams, which I tackled by sanding and then applying two coats of epoxy primer and two coats of one-component paint for metals.

The mast itself was a bigger project because I wanted to install two inner forestay eyes, backing plates for running backstays, as well as mast steps. With the steps on order from Baseline Marine, I first dealt with the inner forestay fittings. I already had an inner forestay fitting which was badly installed by local riggers many years ago. This fitting was high up the mast so that no running backstays were required, but was not perfectly centred so the forces pulled unevenly. More worryingly, it was installed without any anti-corrosion paste and the surrounding aluminium had started to corrode. As I wanted to move it dead-centre yet keep the original height position, the new fitting had to be wide enough to not just cover but also go beyond the old slot and rivet holes At first, I thought of asking a welder to come over and fill them in but as that would have been two complicated, I filled the slot with JB Weld Epoxy Putty for metals and designed a very wide fitting which I then had fabricated out of 3mm stainless steel plate. The fitting comprises a very wide cover plate and, most importantly, inner flanges that are just as wide, in effect sandwiching the mast wall in between.

Nicholas
Attachments
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It all starts with a drawing. These are the attachment points for the two inner forestays and the running backstays. The green line represents the position of the existing inner forestay, which I retained. More accurately, it's a Solent stay, which allows you to fly any headsail on hanks. For a No 4 Genoa or a storm jib, the second inner forestay mounted lower is a better solution.
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For the wire terminals, I chose Hi-Mod eyes which perfectly match the fork terminals on the Hasselfors rigging screws (11mm hole for a 10.5mm pin).
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Chainplates and backing plates polished, and galvanised beams primed and painted.
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Deck eye bolts cleaned, polished and labelled
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Following the advice of a rigger, I made this UV-resistant PVC gasket to act as a barrier between the outer mast wall and the stainless steel cover, in order to prevent electrolysis. He said that when dealing with large areas of dissimilar metals, applying an anti-corrosion compound may not be enough.
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The sides of the split backing plates which will come into contact with the inner mast wall are given a liberal coating of Duralac.
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The backing plates are firmly held together to facilitate riveting.
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Nicholas Koligiannis
Moments of Clarity
Hull No. 334

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