Firefly MKII Centreboard Case

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gozzy
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Firefly MKII Centreboard Case

Post by gozzy » Mon Jan 14, 2008 12:25 am

Hi just found this forum so here goes my first post.

I am hoping to refit a new centreboard case to my firefly and was after some advice. I have been on the chat pages on http://www.fireflysailing.co.uk but the page is down at the moment.

I have recorded my progress so far and was wandering if someone could take a look and give me some pointers.

http://www.axmi49.dsl.pipex.com/

Thanks in advance

Lee

PS The main picture on my site is of a recently restored firefly that belongs to, I think Rupert who is a member of this forum.
Hope he doesnt mind :?

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Ed
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Post by Ed » Mon Jan 14, 2008 11:06 am

Well it is like you say.....

Best job would be to pull out the centre-board case, re-build hog and hull and put back case.

But I don't think you have to do this.....

I am afraid I didn't after I had similar damage to hull along centreboard case bottom and hull. I had all together about 20 -24 inches of hole running along both sides of hull, with similar damage to hog. It wasn't one consistent hole but maybe 2-3 holes each side. The worst were big enough to be able to put all fingers through to palm of hand.

I also didn't after I put my foot through rotten side of centre-board case.

The beauty of this construction is you can just cut away rot until you have good wood, cut mitres into good wood, then cut and fit pieces to fit holes and just build up till the hole is no more. As you are not using enormous bits, you can afford to buy (or find from other sources) some really nice bits of mahogany to replace the bits you cut out. I found some 1m lenghts of nice 8x8mm mahogany in a model shop and used those to replace edges on hog running down most of case.

I am not saying this is the best way.....which is of course to pull out the case......but that is quite a bit of work....and you don't have to do it that way. I guess a deciding factor would be what the condition of the case is other than the shown damage. If that is all you have, I would certainly be tempted to just repair the damage locally.

I know it looks a bit bad at moment, but it really is only a few hours of work to fix it.....and its great fun work.

cheers

eib
Ed Bremner
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Garry R
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Post by Garry R » Mon Jan 14, 2008 11:40 am

Allied to this topic Ed I have now just about stripped off the blue, red, white blue etc paint from Vivette and have come across a couple of "problem" areas. On the outside (inside looks OK) at the bow at the bottom of the stem and at the transom there has obviously been some rot and the area looks as if the previous repairer has filled in with epoxy and faired it off. What would be the best way to get rid of this rather solid mass (it's not large area stuff) - just cut back and hot chisel away and re-fix agba strip? It's just cosmetic actually as I want to varnish the hull. As I said the inside looks OK. I also wanted to know if you just butt join the replacement agba or do you scarf it?

Another problem is that there has been a large hole in the hull (right through which has been repaired with plywood set in and taped around the edges and then faired again with some sort of filler. Would it be possible to cut back the 2-3mm on the outside and set in agba and then do the same on the inside leaving a bit of ply in the middle. This is in a flat area of the hull so no problems of extreme curve in the veneer.

In relation to the centreboard case problem I have had to reglue the veneers to the hog between the aft end of the case as there was a gap down the centre line where the veneer ends had rotted. I cut back to good wood and I set in a piece of mahogany (about 1.5cm wide strip)between the two hull sides onto the hog and it looks to have been a success. A Chris Barlow tip is to cover battens for holding glued parts down using parcel tape - epoxy won't bind to that.

A night off scratch and scrape tonight thank goodness. Resume the torture tomorrow!!

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Ed
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Post by Ed » Mon Jan 14, 2008 3:01 pm

Re Solid Mass of epoxy....

yup just cut it out and repair properly with agba veneer.

Re: Butt or Scarf join...

the sides running with grain I normally butt join. the end grain joins I try and get a little bit of a scarf....but not much of one. It depends on how you create your replacement bit of veneer. I cut over size and then cut/plane/sand each of the for sides until it just fits in. I tend to slightly taper veneer and then push it into the gap, leaving hopefully no gaps at all.

Re: Hole filled with Ply...

I see no problem with this as long as the inner ply is flat and follows contours of hull fully. You want to cut outer layer of veneer to larger size than the hole filled by ply and then fill that with veneer, held down with staples, battens and weights. You can then do same on inside, replacing a larger area with new veneer than hole filled with Ply. Once you have done this you should not be able to see the ply at all.

Brown parcel tape is normally pretty good as a release tape. Be careful though....some are better than others and I have had problems with epoxy sticking to brown tape. Most epoxy suppliers sell a 'release-tape' which looks like a clear parcel tape. it does not cost much and works a bit better, or more reliably. Having said that, I normally use brown tape that I have already tested. Remember that strips of mylar can also work as a good release and with a little care you can get a very good finish this way.

A night off is always good.....but at least you don't have any ribs this time.

I am still trying to get my head around the idea that I have really got to strip my Jollyboat inside and out this year before she goes back on the water......When this is going to happen and 'where' as she is too big for my workshop is anyones guess!!

cheers

eib
Ed Bremner
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Jollyboat J3
Firefly F2942
IC GBR314 ex S51 - 1970 Slurp
MR 638 - Please come and take it away
Phelps Scull
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gozzy
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Post by gozzy » Mon Jan 14, 2008 5:16 pm

Hi and thanks for the quick reply,

You should have seen that the centreboard case is now completely removed from the boat and so the decision has been made :?

As far as I can see its the hog and hull i need to concentrate on now. There are a lot of previous repairs underneath and I wanted to try to replace the middle section of the boat.

The problem is I have no clue how or where to start. Is it best to repair the hog first and then repair the wood around it? Can I cut out a large peice of wood and then attach a new peice for the hull? This would give two new sections either side of the hog that will leave me with no rot at all.

Also now the centre board case is out as shown on my pictures I have hung the boat on its side to try to support it better. Can i still carry on sanding other areas or should I wait until a new case is fitted or at least wait until the hog is repaired?

Thanks in advance

PS Garry do you have any pictures of your progress you could send me as it seems you are ahead of me???

Lee

Garry R
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Post by Garry R » Mon Jan 14, 2008 5:43 pm

Hi Lee

My centreboard case is not as bad as yours nor is the hog to all intents and purposes. There was some rot at the ends of the agba from c'board to transom but this is sorted by cutting back - only a cm or so and I glued that down and filled the gap. There is a little rot at the forward end of the c'board case as well - the agba rather than the case so that is a cut out and replace job. There is some epoxy to dig out of a couple of patches for cosmetic reasons and replace with veneer. Apart from that I don't have a huge job to do. Ed and Rupert have most experience with this sort of stuff - Up to now I have had clinker boats with ribs so this is a new experience. I will try to take some photos of what I have done as I go along but as I said I think your repair is more detailed than mine.

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neil
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Post by neil » Mon Jan 14, 2008 6:09 pm

Ed wrote: I am still trying to get my head around the idea that I have really got to strip my Jollyboat inside and out this year before she goes back on the water......When this is going to happen and 'where' as she is too big for my workshop is anyones guess!!
Your workshop maybe too small, but I reckon she'd fit in the house OK.
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Michael Brigg
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Post by Michael Brigg » Mon Jan 14, 2008 9:50 pm

The main picture on my site is of a recently restored firefly that belongs to, I think Rupert who is a member of this forum.
Hope he doesnt mind
Hi Gozzy,
What a great web site you are building up. I particularly like the picture introducing your intention to restore your boat yo professional standard and I suspect you will do alot better as there is no substitute for a personal touch.

The "main picture" belongs to me, also a relative newcomer to these pages. I think you said you are from Portsmouth area so we will be able to compare the two in "before and after condition" (and final cost) as I am based in Gosport.

Here is a link to Haines Boatyard in Itchenor who carried out my work.

http://www.hainesboatyard.com/Firefly%20restoration.htm

Regrettably I have neither the skills nor time needed on this sort of project and I am mightily impressed by your speed of progress. Fortunately my pocket has been (almost ) long enough to keep up with the work that Mr Haines found in the course of repairs although any furthur projects are going to need a sharp upturn in the economy and certainly no more wobbles from places like Northern Rock!. Interestingly by far the most expensive bit was stripping and revarnishing, so perhaps I could have done most of this myself. I confess I've become a bit of an armchair enthusiast at this sort of thing.

I think we have already corresponded on the firefly site about things like Masts and Mark2 vs other marks and a similar thread exists on Vivettes Deck layout

As far as storing your hull on it's side is concerned I would be inclined to put braces across the topside to prevent any distortion to the hull shape as alot of the internal stuff has been removed. Have a look if you can at the link from the Firefly site to Cumulus' restoration, or contact her owner via the membership secretary. He also did a Centreboard replacement I think and the series shows the stripped out hull with quite extensive bracinig fixed across between the gunwhales during the restoration until he put stuff back in.

Keep on addind those pictures!

best wishes
Michael Brigg

Rupert
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Post by Rupert » Tue Jan 15, 2008 10:04 am

Yep, Michael's boat, not ours!
Agree strongly about the bracing, and would also say it is worth getting the structure back in before you do any more work, as you don't want to end up with something that measures as a National 12!
As far as the work goes, I would, I think, rebuild the hog first, then build the planking back up on that before putting a keel back on the bottom. You will than have your hull shape back in order to produce a plate case that fits. One way round the plate case problem, that my brother had done to his boat was to fit one that had been removed from a boat written off in a different way. Not only did it lessen the work, but the "look" was right. Finding one, especially with the Firefly forum off line, might be tricky, but contact Ray Smith of Tomato boats or Brian Herring (the numbers are probebly on the Freddie site somewhere - maybe as measurers?) to see if they know of one.
The Cumulus restoration is well worth a look.
Rupert

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Ed
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Post by Ed » Tue Jan 15, 2008 12:09 pm

Doesn't Ray Smith sell centre-board cases already made up or at least with all bits cut and ready to fit?

cheers

eib
Ed Bremner
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Firefly F2942
IC GBR314 ex S51 - 1970 Slurp
MR 638 - Please come and take it away
Phelps Scull
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gozzy
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Post by gozzy » Tue Jan 15, 2008 2:55 pm

Hi Michael

I remember now all the great advice you gave me on the firefly chat pages. I am based in North Wales so quite a way from Porstmouth. Hope you dont mind me using your picture its just I use that when its all getting a bit stressfull - it reminds me what I'm trying to achieve :D

I have been onto the firefly site and the cumulus link is down I think. I have mailed to try to get the details of the owner.

With regard to bracing im not sure exactly what is needed - do I just need a strap wrapped around the middle of the boat?

Hog Repair - Can I cut a section of the hog out completely and replace? Or should I try to fill and repair the hog with epoxy fillers?

Due to the job being more indepth than I first thought I think I need a book to read - I cant expect people to advise me through the whole process! Can anyone recommend a good book that will be relevant to the work im doing? I have seen one called Wooden Boat Renovation: New Life for Old Boats Using Modern Methods, its on amazon.

Thanks to everyone who has responded

Lee

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Ed
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Post by Ed » Tue Jan 15, 2008 3:48 pm

Not really sure how much a book will help.

It really is pretty simple though.

You need to find out what is rotten, cut it out and replace with good wood.

Once you have got the case out, the construction is pretty easy to work out, so you just put it back together as close to what it was originally.

just start with the most integral and strong bit and then work outwards ending up with the more cosmetic stuff.

Done like this you shouldn't need to use epoxy fillers much, but will certainly want to use epoxy to stick it all together, maybe with some carefully used fillets for extra strength.

I, also would worry a little about the shell being left for too long on its gunwhales......I am sure some braces would help....but all in all I would just try and not do it....or only for as short a time as possible. this is not really due to the case being out (though it won't help), but to be honest, I wouldn't want to leave any boat on its edge for long.

cheers

eib
Ed Bremner
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Jollyboat J3
Firefly F2942
IC GBR314 ex S51 - 1970 Slurp
MR 638 - Please come and take it away
Phelps Scull
Bathurst Whiff - looking for someone to love it

Garry R
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Post by Garry R » Tue Jan 15, 2008 4:05 pm

I would agree 100% with Ed as with the glueing of the hull veneers to the hog being adrift as I understand is the case, the hull will lose shape when she is on her edge ie she will sag and twist. The first thing to do is get her onto her keel side down and get some braces across her. Don't put the braces on her when she is on edge or any distortion will get fixed in. The best way to get the correct shape back is to re-fit the thwart into the original position with the original screw holes - even if temporarily - this will at least give you lateral stability. THEN fix cross braces nearer the transom. Dont be tempted to remove the decks until you get the hull firmed up.

gozzy
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Post by gozzy » Tue Jan 15, 2008 8:08 pm

Hi Guys and thanks for all your help so far,

What is meant by bracing the boat (I know it sounds thick :oops: ) if I sit the boat on the keel side the bottom will sag inwards as there is no centreboard case in it?

I have updated my website with more detailed pics of the hog and also a plan of what my next steps are.
Please can you take a look at http://www.axmi49.dsl.pipex.com/Project%20Plan.html and let me know your thoughts please?

Thanks

Lee

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Ed
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Post by Ed » Tue Jan 15, 2008 8:20 pm

I can't quite see where the red lines go.....

but it looks to me like you are intending on cutting out a large panel maybe 6in either side of hogg for whole length of centre-board case? is that right?

Sounds or looks rather dramatic to me.

Is there really that much rot?

Personally I would be both careful to remove all rot.....but also try and not remove too much good wood.

the other thing is to remember that you need to cut the outer veneers on inside and outside shell a further couple of inches beyond the inner veneers. you use the inner veneers to guide the lie of the outer bits and provide strength.

Personally I would not remove any good wood at all. If needed for cosmetic reasons I would remove the outer veneers (inside and out) and just lie new veneers over the old inner veneers.

It is much easier to repair veneers rather than replace whole large areas, which although not hard....does provide more of a challenge as you may need to build some kind of mould underneath.

mmmmmmmmmmmmmmmmmmm...........................

If you have not cut anything yet.....take a couple of steps back and have a good think. If you have, don't worry too much - everything is re-buildable....but it may be a bit more work.

cheers

eib
Ed Bremner
CVRDA


Jollyboat J3
Firefly F2942
IC GBR314 ex S51 - 1970 Slurp
MR 638 - Please come and take it away
Phelps Scull
Bathurst Whiff - looking for someone to love it

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