A couple of Firefly questions

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Michael4
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A couple of Firefly questions

Post by Michael4 »

Hi, I'm after a little advice to help me with my Firefly project.

Extending the mast.
I have an old Reynolds mast and I also have the bottom three feet including foot from another. I intend to pull the foot out of the complete mast, fashion a nicely fitting 6'' hardwood plug and then extend the mast using the appropriate length sawn from the spare bit. I will probably epoxy the whole thing together. Does this seem an OK approach? The mast itself is not in the first flush of youth so I would be unwilling to spend too much on the exercise (although presumably I will have to spend on shrouds etc)

Positioning jib sheet fairleads/tracks
The boat has MK I decks. I intend to bring the sheets to the thwart. I have a couple of useable tracks with fairleads and jammers (curiously they are Australian), they seem worth using. As I understand it, the best places to position the fairlead would just allow the sheet to clear the side deck. Shall I run the tracks along the the thwart, fore and aft or diagonally across the thwart? I intend to sail mostly singlehanded and care little for the crew's posterior. What have others done?

Thanks in advance

Michael
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Ed
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Re: A couple of Firefly questions

Post by Ed »

Extending the mast:

maybe... I have an extended Proctor C with an extension made from another bit of mast and this works OK, although after a few years it is beginning to wobble a fair bit. There is quite a bit of stress on the mast here and I would worry a bit about using a wood core, even if you wrapped it in epoxy. Better to fabricate from metal and use the old mast to make a bit of core by cutting out a bit of section so it fits inside. I would imagine that the class association would be happy with this, but if you are intending on class racing, it might be worthwhile checking with them.

Jib Fairleads:

I have Mk1 decks and as you say, have the sheet fairleads on the thwart, just blocks attached straight to the thwart on deck-rings, with some tufnol pads to protect wood. As you say, the sheets just clear the side deck. As I said, I wouldn't use the tracks as not really needed. If sailing single-handed, I would then pull the sheets back across the boat and cleat them on the windward side deck. I find I can sail single-handed, sitting out and make small adjustements to jib trim with my foot/leg/knee on the sheet as it crosses the boat.

hope this helps

eib
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chris
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Re: A couple of Firefly questions

Post by chris »

I have used a merlin mast that was shortened before I got the boat. The (ali) mast was cut and the 10" bit removed was used as a collar to wrap around the join and riveted in place this has lasted at least 20 years. The problem with wood is that if it swells with damp it will most likely split something.
JimC
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Re: A couple of Firefly questions

Post by JimC »

To extend a mast I'd butt join the two and sleeve. In fact if I could I'd look to find the bottom of a.n.other spar just the right diameter to sleeve internally and use that as an extension, running it right up to gooseneck height, and make the extension piece of the original primarily cosmetic.
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Re: A couple of Firefly questions

Post by Ed »

Yes, JimC is pretty much describing what I was trying to say....only clearer.

Images of how my Proctor C (Firefly) was extended are here:

https://goo.gl/photos/PYbeuwrouQzbg42C8

Image

the inner sleeve was made with another section of mast that was then cut longitudinally to make it small enough to fit inside the mast and then riveted into place.

I think mine was made by Tomatoe Boats?

eib
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Re: A couple of Firefly questions

Post by chris »

join.jpg
An alternative method:
This way the thrust is taken by the butt joint to the extra bit of mast rather than just the rivets:
Michael4
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Re: A couple of Firefly questions

Post by Michael4 »

ImageIMG_2423 by dralowid, on Flickr
This is the base of the mast in question

ImageIMG_2424 by dralowid, on Flickr
This is the bit I have to do the job

ImageIMG_2425 by dralowid, on Flickr
This is the cross section (OK so the end looks tatty but the rest looks much better)

So, listening to what you have said I plan to:

1) Remove foot from mast
2) Cut necessary extension from spare bit including foot (which, from what I can remember is about three inches? Will check the rules)
3) Use the remainder to make an inner sleeve by cutting out the luff groove section leaving as big a horseshoe shape as I can. With those brackets I will not really be able to make an outer sleeve.
4) Rivet together

I notice that one mast base has a bronze(?) inset in the foot (ie for the swivel bearing) whereas the other is plain ally. I guess there isn't much in it?

Hoping I have understood this correctly and thanks,

Michael
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Re: A couple of Firefly questions

Post by Ed »

If memory serves....and Mike or Rupe will remind me if I am wrong....

the allowed extension is 75mm or 3in and is the same as the extension given by replacing the flat mast foot (as you have) with the high foot with sheeves in it (as I have).

Does that help?

I seem to remember quite a bit of discussion as to whether if were going to add in 75mm, whether it was better to do it higher up, where there is less stress, but you have two joins against adding to the bottom, where there is one join but much more stress. I took the 'add to bottom' option and it has worked fine, although it is now showing signs of quite a bit of 'wobble' whereas it was very tight for the first few years. (Don't - MBrigg)

cheers

eib
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JimC
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Re: A couple of Firefly questions

Post by JimC »

I would be inclined to take all the fittings off that impinge on a potential sleeved area and remount them with rivets that go through both pieces, and that would include the gooseneck fitting if its a fixed one (don't suppose it is though). The longer the sleeve the better really. Don't forget the yellow slime... I'd be inclined to use jointing compound between sleeve and original tube: the lessthat rivets are doing the better.
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Re: A couple of Firefly questions

Post by Rupert »

Offhand, I can't remember whether there was a Max length on the sleeve in the rules. Certainly I can't remember anyone putting one all the way to deck level, let alone gooseneck. I'd be very wary about what strength is left in a Reynolds mast, though, and I think I'd use new metal as the sleeve.
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Re: A couple of Firefly questions

Post by GAv »

There is an awful lot of tension low down on such a mast, from the kicker and main, not to mention the weight transfer from the centre board when the craft is healed over, and personally I wouldn't trust a couple of rivets, unless you have actually sleeved it internally, then you have potential problems with halyards jamming.
My fist little boat, an Adventurer had design issues with masts splitting at the halleyard pulley lower points.
The boat was over 20 years old and I found this had happened.
Someone I know had a new Mast from a Gull and for £40 pounds(the exces was £50) I bought it and found it was longer.
I did rivet the old gooseneck bracket onto the new mast but left the one already on it in situ.
Then I found that whilst the mod to the gooseneck height,gave more clearance,for my big bonce, but it unbalanced the boat, so I held my breath and hacked a couple of inches off the base of the mast, and immediately she handled better.
I used a piece of the old mast to make up a boom on my first Streaker and put a swivel on the gooseneck not to reef the sail, but so as I could roll the sail around it and put the overboon cover on, after Wednesday evening Spring Summer and Autumn sessions.
I just relisted my old Firefly mast on EBay incidentally.
Michael4
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Re: A couple of Firefly questions

Post by Michael4 »

I looked at an extended old Reynolds mast this afternoon, the extension was simply right at the bottom, seemed firm enough and apparently had been done some years ago. I could make the join as high as just under the deck but somehow I don't think that would make a lot of difference and would be in the gooseneck(fixed)/kicker triangle.

Alternatively has anyone got a spare mast foot with sheaves in that would fit a Reynolds mast profile? As Ed says, that would give me my 3 inches.

I'll ponder some more before chopping things up but I am under no illusions as to the long term future of this mast, after all, it may only be 63 years old!

Michael
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Re: A couple of Firefly questions

Post by Rupert »

Any sheave block thing will have a tenon on the bottom, not a hole for a rotating mast, I'd have thought?
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Michael4
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Re: A couple of Firefly questions

Post by Michael4 »

Rupert wrote:Any sheave block thing will have a tenon on the bottom, not a hole for a rotating mast, I'd have thought?
Of course, should have thought of that. Am now practising my riveting sklils

Michael
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Michael Brigg
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Re: A couple of Firefly questions

Post by Michael Brigg »

One of your real problems here is the Reynolds mast...

These for their time were beautiful bits of engineering and combined the best of the trade in rcing wooden rowing oars, Rigging and aluminium technology. It is important to realise that if you mess with any part of it, you may affect another bit unexpectedly.

A wise man once said...

Image

Personally I feel it is a shame to "gild the lily" so to speak and any alteration is likely to end in tears.

However, if it must be done then you must consider few points.

The mast was designed to be watertight, and this is a vital point in preserving its health as it is not anodised so any water inside (especially if salty) is a death sentence. The thickness of the aluminium extrusion is also rather thin (compare the weight of Reynolds against a proctor... the difference is remarkable.) This means that the strength must be derived from the plug (or sleeve) rather than the rivets. In fact every rivet adds to the likelihood of the fix going wrong, so I really would favour a plug solution over a sleeve. There is, and cannot be any internal running rigging, and your main halyard must be capable of going all the way to the foot inside the Luff groove where it turns around a (rather rudimentary) pulley.

To preserve the water tight principle I would recommend a solid wooden internal plug and use the same construction method as the wooden top mast. This is simply rammed in to the hilt with brute force (about 8inches I think) and then fixed in position with large rivet that goes all through the mast, and wood (and so doesn't break the waterproof seal.)

It is an aluminium rivet, so it doesn't corrode either, and no need for the Zinc Chromate paste to seal it.

Make a foot first (cut to 8" ) with an 8" wooden plug sticking out of it, and ram this into the bottom of your (cut to size) prepared mast. Fix with a through mast rivet as before.

You can sleeve it on top if you wish but I think that would be more for cosmesis than strength and may make the halyard arrangements difficult.

Also, especially on the rather thin extrusion of the reynolds, in principle, the fewer rivets the better!

If your plan is for mostly single handed work, you won't want too much kicker tension anyway but I thing this method will cope as the tension is always in one plane (it being a rotating mast, the boom and kicker mechanism turns with the mast.) Furthermore it being an older style of rig, there is less need for extreme kicker tension as the mast will bend quite easily without much leverage needed. Also, we know that these older boats (in the national 12 pre war build of which the firefly was a development) were originally rigged with wooden masts, so we know that wood will be more than strong enough. It has the added advantage that it is easily worked and if required can be assisted with a bit of epoxy to get a decent fit.

...and finally, if there is only one thing you do with a Reynolds mast, make sure that the collar fits snugly and rotates easily in the mast gate. If this has ANY inclination to jam, then your work will be wasted as the jammed collar will cause the gooseneck (or worse the mast itself) to break or develop a stress crack. (Difficult to fix, and usually a death sentence.) It is well worth putting in a gasket of greased tufnol (cut from an old batten) securely fixed in all the way round the mast gate to ensure a smooth friction free rotating action. (You may have to sand down the mast collar to make it fit easily and if you do it must be kept perfectly circular! Really round... any elliptical distortion will make it jam.
Michael Brigg
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