Mainsail track rivets
 

Hi everyone,

I'm refitting a new to me 1979 Morgan 31 designed by Angelo Lavranos and built in South Africa. Currently I'm taking care of the mast and standing rigging. The mast and boom were manufactured by Paul Green Masts also in South Africa.

More info here: http://sailboatdata.com/viewrecord.asp?class_id=6787

When I unstep the mast a few weeks ago the first thing that caught my eye was that many (I would say nearly half) of the rivets that attach the main sail track to the mast were broke, i.e. the head of the rivet was missing.

I proceeded to drill the remaining rivets in order to remove the track and re-install with new rivets and most of the rivets would break as soon as the drill bit touched them. All of these rivets, 110 on either side of the track, were aluminum (to my best knowledge) and should have been replaced long ago.

I would also like to add that there are other rivets in the mast, in the area around the splice of the two sections of the mast and in the stainless steel fittings where the shrouds t-terminals attach. These look much stronger and in better condition but I'd also like to replace them now that I have the mast down.

I must add that while the rivets in the sail track looked dull grey before I drilled them, the other rivets have a bronze like colour on the surface, but drilling them revealed an aluminum like colour bellow that yellowish patina.

My main question is how should I proceed to attach the sail track to the mast:
1. Should I use rivets again and in which case what kind of rivets?
2. Should I tap the spar and use machine stainless steel screws?

I've read that I should use Monel rivets, which I'm having trouble finding as some local companies don't even know what I'm talking about and importing these from overseas seems as the only solution right now. And and expensive one on top of the already expensive Monel rivets.

I was able to find aluminium rivets with steel (non stainless) mandrels but I guess these won't work as the mandrel will just rust causing problems down the road. I was also told by the company selling the aluminium rivets that I can't remove the steel mandrel from the rivet after I install it as the rivet will loose it's strength.

Can I replace all the rivets in the sail track with machine screws? Tapping threads in the 220 holes I have in the spar right now? That sounds like an awful lot of work, but I can do it if it has to be done.

What about the other rivets, those attaching the two sections of the mast, the t-terminals and the spreader fittings? Most of these are countersunk rivets by the way.

Looking forward to your knowledgeable replies.

Regards,
Luis

I'm surprised you can't find monel rivets
Have you tried some of the local companies specializing in fasteners?

Any local rigger?

Hi,

It's sad but true. I called several companies specialised in fasteners, I can find aluminium rivets and stainless steel 316 rivets. But not monel rivets.

A Selden distributor / rigger was able to provide monel rivets at $1.88 each which I find extremely overpriced.

--
Luis

Since you live in EU you could try sourcing inside EU?
I checked price here in Norway 100 4.8 x 12.7 is 748 NOK = $ 0.96 each
Norway is not EU but prices here are almost the same.

You could try Benns in Sweden (EU), drop them a mail (in English) and get an offer.
Here is a link to showing Swedish price for ten http://www.benns.se/en/mast-rigg/ovr...128-mm-10-pack

Hi knuterikt,

Thank you the link. Today I found a source in the UK with reasonable prices. Around €42 for every pack of 100.

In the product description they have:

Monel (nickel copper) alloy rivets
Corrosion resistant rivets for use with aluminium and stainless
Particularly suitable for marine applications, coastal, saltwater spray
Often used for securing fittings to sailboat masts and spars
Body: Monel
Mandrel: Seel zinc plated

Here is a link: http://www.shop4fasteners.co.uk/rive...ts/c-24/p-4600

I have one concern though. With the mandrel being zinc plated steel it will certainly corrode inside the rivet which is not good. Should the remaining of the mandrel be pushed out of the rivet? And if so, won't this make the rivet weaker?

What is the mandrel of the rivets you found in Norway made of, do you know?

Regards,
Luis

I always remove the mandrel, this is in accodance with Selden instrictions on mounting hardware on their mast, Using correct length rivet this is easily done using a pin punch.
read here step 11 http://www.seldenmast.com/files/1426...5-099-SETF.pdf

I always use Duralac to isolate dissimilar metals. (I the UK company sells that to)

Even if your mast is not from Selden you should have a look at this http://www.seldenmast.com/en/technical_info.html Lots of useful information.

Hi knuterikt,

Thank you for the quick reply and the links.
The Selden rigging document is extremely interesting.

Regards,
Luis