centreboards for vintage yots

[paul turner]

I am currently restoring N2359 Shotgun and would appreciate some advice regarding the centreboard/case. The existing c/board is (very rusty) steel wobbling about in a 9/16 solid wood case. Any thoughts on a replacement of more modern/lighter variety, or even how to widen the case in situ (to take a wooden plate?) would be appreciated. The current board hooks over a hidden pin; there is no bolt hole or hanger!
For the record Shotgun is real oddity; see the info on the boat database. She needs some serious weight reduction so the bilge keels and keel bands have gone and the central keel has had to be reduced because of damage. Several small sections of planking have rotted; if anyone has, or knows where I can get, three 6" x 6" sections of 1/4" mahogany marine 5 ply, please let me know. The mainsheet traveller track has gone and the transom top is to be cut down provide wood to fill in damage/rot on the lower transom and rotten bung holes.
And advice on the removal of the smell of cat wee would also be helpful; several applications of hot soapy water and bleach haven't worked!
And finally - I have the original transom and attached planking which were cut off when Mike Nokes redesgned the boat; wondered if it might make a nice trophy for the first clinker boat at the Burton Week?
Paul N2020/2359/2487/3157

[johnk]

An aluminium board would be the simplest way to lose weight without widening the C/B case. I am a little surprised that in 1966 Mike Nokes was still building boats with steel C/Bs.

The next stage is to make a carbon fibre board which will be lighter still.

To fit a wooden board you will need to rebuild the C/B case since a wooden board that fits your present case will not be strong enough.

[Tim Gatti]

Paul - widening the plate case sounds like a major re-construction job, on top of all the other work needed - or maybe your carpenter is short of other work?Would suggest you might be better off considering a slotted aluminium plate with some tufnol side-cheeks epoxied on to take up the space. (N493 has a similar plate which works really well.) On the ply front - are you wanting to match existing wood? Could probably fabricate something up for you from more modern Robbins decking ply (I'm having to do that to make up 8mm thick plank patches for N2255 - but she's painted inside and out as you know so tonal differences in the wood won't be seen).  On the cat wee side of things - can only suggest you strip offending areas back to bare wood with Nitromors or similar, scrub thoroughly with wire wool and white spirit then re-varnish.  Failing that try Chanel No 5 liberally applied.
I think the back end of a National 12 - however nicely presented, would be a bit impractical as a trophy - it would need a lot of wall space, or a huge mantlepiece to display it. And for those who choose not to display their trophies - it probably wouldn't fit through most loft access hatches either! Tim (too many 12's to mention)

[paul turner]

Thanks Guys for such instant responses.
1. Aluminium plate - where could I get one from? Are they much lighter? I might talk to Cpt Carbon at FOS (but he will take the pxss something rotten as I have campaigned against using carbon on any vintage/clinker boats but possibly "needs must..."). Is there no wonderful machine/device that you can stick down the centreboard to plane it wider?
2. Trying to keep the boat varnished throughout if possible but can't be too fussy about exactly matching colour! Ken G is looking through his collection of bits but is not hopeful; only need three small squares!
3. Cat wee is mostly eminating from the front bouyancy tank and under the foredeck so might try Jeyes fluid next? :-/
Supplementary questions: The back of the centreboard has lifted (1/4"), cracked forwards 18" and twisted slightly to port  - assume best way to repair is to screw back into position through the (much reduced) keel? Rubbing strakes have substantially rotted each side; any reason why I shouldn't just cut back to the solid side decks and round off? Will retain what there is/repair what is left from the bow to just past the shrouds for protection, unless it's worth taking that off too to reduce weight. It's not a pretty boat!
Any more help/advice welcome! P :K)

[Tim Gatti]

Paul - try a local fabrication shop for an ali plate - and take the old steel one along for a template.  With your talents you should be able to blag an offcut and get them to machine it up for you.  Cptn Carbon won't be the only one taking the pxss something rotten if you opt for the black magic route.  Does the boat really justify that sort of expense?
Only tool I can think of would be a large chainsaw - but by the sound of it, the whole plate case might need to come out if its lifting and separating from the hog to the extent you describe. 
Rubbing strakes/gunwhales - protect the end grain of the deck ply, add strength and shape to the boat, deflect spray and give your bum something comfortable to sit out over. Doing without them won't save much weight - and wouldn't recommend it. But as you say - Shotgun is a real oddity so at least you'd be maintaining the theme!
Not sure which smells worse - cat wee or Jeyes Fluid.  I think the Chanel option still has a lot to offer, or maybe something more manly if you prefer.

Any chance of posting any photos so we can see what you're talking about?

[johnk]

Aluminium is about 1/3 the density of steel. Its modulus is about 1/3 that of steel so, as stiffness is proportional to the cube of thickness, an aluminium plate has to be 50% thicker than steel. Thus the weight saving going from steel to aluminium is 50% of the steel C/B weight.

Fireflies have aluminium C/Bs I think.

If possible go for a corrosion resistant alloy of Aluminium. The stiffness will not change significantly.

[gerry ledger]

Hi Paul, I think Fireflys still use ally plateswhich shouldnt be too different you could try Rondar who build them.or I could always put a new case in for you!!!!

[paul turner]

Thanks Boyz
Gattiman - boat doesnt really justify going over to the dark side, nor the pain of the "greivious bodily of the ear 'oles". Aware of less comfy setting out but I have plenty of padding and the side decks are standard W&C solid mahogany plus a stringer underneath on the outside AND a solid piece internal across the join between the foredeck and sides - looks like serious over-engineering! So will keep the overhang at the front for spray (even for the speeds I am likely to achieve) and reduce cost of replacing to rear of shrouds. Chanel? As in English Channel? Anyway I like the smell of Jeyes - well I have had to get used to the stuff which is oft used to disinfect the stables at the farm and my wetsuit!
Gattiman/JohnK/Gerry - will persue aluminium routes suggested.
Gerry - have emailed you direct.
Cheers, Paul
And she has a very odd mast which appears to be a bendy "C" section with very low spreaders and a spinnaker halyard!

[Dodgy rigging (Guest)]

Sounds like a Lark mast, they have been used with success once the spreaders are moved up approx 18 inches, just fill the holes with rivets.  Good luck with the rest.

[ken goddard]

Hey, Paul! Why didn't you ask me? I only live about 10 miles from you and and I have had an alloy plate in one of my sheds which has been looking for a home for years! It's off N.1425 "Liz",ex Earlswood Lakes. The only problem is that it has a curved leading edge and a straight trailing edge, to suit the very heavy keel rocker of a Proctor Mk.6. You could try it to see if it fits.
Regards
Ken G.  

[paul turner]

Sorry Ken - I never thought to ask but will ring you. I'm still desperate for three 6" x 6" 1/4 marine ply pieces to repair the planking around the transom if anyone out there has any bits, please! Cheers, Paul :K)

[kevquinn (Guest)]

Hi
just reading your post, to get rid of the smell of CAT Pee the best way is to use a mixture of a hydrogen peroxide cleaner (like oxy clean or cilit Bang), baking powder & some washing up liquid, the chemical reaction breaks down the protiens in the cat pee. or the other way is white vinegar.
I've used the first version & it works well
 
Kev