Firefly boaw fitting fasteners

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Graham T
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Firefly boaw fitting fasteners

Post by Graham T »

Just doing a rapid re-deck of a Fairy Firefly. The bronze bow fitting was held in place with an odd assortment of stainless screws and a couple of round head stainless bolts. I am assuming these were not original so plan to replace them. Would it originally have been screwed down or through bolted or a combination? Bronze or brass fastenings? Or would it just be easier and better to just use stainless? I don't like mixing metals but it seems to have been fine like this for a long time....

Graham
Graham T
Osprey 1340, Osprey 1245, Osprey 55, Miracle 1358, Laser heap, ancient Mirror kit half assembled, Project Miracle in need of decks........
Kielder Water Sailing Club
Rupert
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Re: Firefly boaw fitting fasteners

Post by Rupert »

I seem to remember it was mostly brass screws, but I have memories (vague) of trying to get brass bolts out from up there somewhere - might have been the roller for the jib halyard, though.
Rupert
Michael Brigg
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Re: Firefly boaw fitting fasteners

Post by Michael Brigg »

This really depends on how you are planning to rig your boat.

Historically the firefly was rigged with a rotating mast. The forestay is a bit of a supernumerary as all of the strain at the front is taken by the jib halyard/luff wire.

...but how to rig the halyard to a fixed tension when the mast rotates.

The answer was to rig the halyard from the head, up to a turning block that is itself able to run freely around a wire strop that runs from the shroud fittings on either side of the mast. This allows the mast to rotate without altering the forestay/halyard tension.

Here is a picture of the arrangement:

http://s225.photobucket.com/user/michae ... ort=3&o=16

From the upper turning block the halyard is led back down the forestay, (usually through the jib hanks,) through a hole in the Bronze bow fitting and around a bow roller/turning block high up on the inner aspect of the stem, underneath the foredeck. From here the halyard tail would be wrapped around two cleats usually under the Starboard deck. The original primitive, but rather ingenious method of tensioning was to pull the halyard sideways onto a metal rack, under the deck. You may have seen/ still have the rack and cleats under the deck beams.

So the load of rig tension is shared at the front between the block under the deck, and your bronze plate. These were held originally with 8 x 1" brass screws. With full kicker and the Boom pulled in up wind until it is block to block, this can still generate a very high rig loading, and with modern sails and kicker and sailing styles mean that screws are not really enough, and you would be well advised to through bolt at least 4 of the holes, and the under deck pulley while you have the deck off to allow easy access.

I always recommend similar beefing up of your shroud fittings. There is always a danger that screws will pull out of the wood, and if they are original brass, then unless regularly replaced/checked (which itself will weaken the fitting) nail sickness is always a possibility, and will cause sudden mast breaking failure.


If you have a fixed mast, the point loading on the bow fitting will be even higher. (Doubled in fact!) as the load is all taken at the bottom, by the tack of the jib, and the halyard turning block at the top is part of the internal halyards that are now possible as you have a fixed mast.

...so definitely use bolts, stainless is OK but yes, do keep an eye out for corrosion and consider using the special yellow sealant paste they use for rivets on an Aluminium mast. (It is called Duralac Jointing compound)

Also, if you have/decide to change to a modern fitting, do get one that has a strip down the stem, as a "Side on" bolt will give you even more peace of mind, and make sure you attach the tack of the jib as far forward as possible.
Michael Brigg
kfz
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Re: Firefly boaw fitting fasteners

Post by kfz »

I wouldnt use Brass Screws for such a structural item. The correct screws to match your bronze fitting would be SiBr. These are fairly expensive, but if you shop around you will find them only approx 2 times the price of A4 stainless. There is no problem with mixing Stainless (A4) with the bronze fitting if you so inclined.

If you replace the fitting its vital as Michael says to get one with screws into the bow stem so the fixings are in sheer. If you have any doubts about the timber then replace.

Kev
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