MERLIN ROCKET FORUM

Topic : replacement decks for sweet charity

I have been reading past postings on redecking and the recent article on Krakatoa.
But for the layman what is the best method of removing the decks? At the moment the favoured method seems to be routering out of all the mateing points of the stucture thus leaving the gunwales and other structure ready for the new decks. This sounds fine but I intend to leave the carlings and gunwales in place, making this method ultra precise.
Is there and more advice or even some photo's?


Posted: 15/10/2005 16:58:11
By: scott 3072
What you propose is more marquetry than boat building! Honestly replacing the gunwhales and the innner bits of the carlins if you want to cover the ply edges is so much easier.


Posted: 16/10/2005 10:51:35
By: Ancient Geek
Not only that it's structural - the gunwhales / inwhales hold the plywood down.


Posted: 16/10/2005 19:54:25
By: Chris
Dont think that Gunwales and inwales hold the ply down? A 4mm edge glue might do it a bit but the stuff under the decks does that I'm sure they do however protect the ply edges and make it look pretty!


Posted: 17/10/2005 11:35:51
By: Pedantic Ancient Geek
I replaced the decks on 1728 (see Spring Magazine 2005) and, yes, it is a fiddly job to do it with the gunwhales/rubbing strake in position and it is more like marquetry.  However you also have to be careful when you take the gunwhales off - A gentle heat from a heat gun will certainly soften any epoxy which might have been used previously.  Also when you come to plane down the new decks after fitting and glueing be careful that you dont overdo the trimming and leave gaps.  I reckon on 1728 the worst gap I left at any point was less than .25 mm and then only in a couple of very small lengths and doing it again I would do even better (not that I want to do it again you understand!!!!) It did take me at least 4 hours work to cut accurately for each half of the foredeck and the same again for each of the sidedecks remembering that there is a neat scarf joint to be made between the fore and side decks at some point.  However epoxy glues with the various spacefilling and strengthening additives mean that you should get a great hold.  If you do as they suggest "on the tin"(!!) and coat the surfaces you are going to glue with an epoxy mix without additive just before the glue with the additives are applied this has the double function of improving the hold and also allows the epoxy to soak into the exposed ply and effectively seals it.  Take your time - measure dozens of times and cut only once is the best advice and never take a huge amount off at any one time. Get loads of G clamps and the best of luck.


Posted: 17/10/2005 12:35:23
By: Garry R
Garry, Just read your article in Spring 2005 magazine.
What was the spec of the ply that you used for the decks? ie what thickness and what wood was the surface veneer from?
ta


Posted: 18/10/2005 08:41:25
By: gb
I was told it was marine ply but to be honest it was very cheap and there is no way that it could be top quality!!  It was 4.5mm.  When I enquired about Robbins better quality ply it was way too expensive to get it to Aberdeen (would have worked out at over £100 per sheet) so I went with the cheap option - perhaps I will regret it.  I stained with Interstain mahogany and then Blakes polyurethane and it has given a nice finish. I also made sure that the edges were well sealed with epoxy before glueing as that, I am sure, is where many of the problems can occurr.  If the surface of ply wears through you can at least see it and do something about it and if you don't then you are asking for trouble.   I will also be storing the boat under cover in winter and make sure that it gets the TLC in future.  Two years now and no sign of any problems.


Posted: 18/10/2005 09:49:30
By: Garry R
I got my ply for 1781 from Robbins, it is a sapele vaneer which they do in 2 different thicknesses of top ply. I went for the thicker and it cost me £57 + VAT per sheet including delivery.
That said the previous time they delivered wood for me they sent it to the other side of the country and i had to hire a van and pick it up from someones garden!!


Posted: 18/10/2005 10:14:35
By: Jeremy3550
Re gaps, Jack Holt once told me that if you sand over a joint immediatly after you've glued it then the wood dust fills the gaps and bingo there are none! Also Bob Hoare used house bricks wrapped in newspaper as weights to hold down decks that were gluing thus avoiding pins and filler and the risk of bruising the ply if you over hit the pin! It worked then and still works now layinf teak venner for teak laid effect decks over ply.


Posted: 18/10/2005 11:55:20
By: Ancient Geek
I used the same brick/paving slab system - amazing how much tension there is on a curved foredeck though, but I did manage without pins.  Advantage of wood dust is that it is the same colour as the wood you are inlaying.  As a matter of interest 1728 is a Bob Hoare build.


Posted: 18/10/2005 12:44:45
By: Garry R
I did one side at a time, which let me clamp one side and then used a a bar clamped at the mast gate and spin shute, which i had added, with a series of wedges under the bar to keep it down. The other edge was clamped to the gunwhale and then shaped after with a new gunwhale on the out side. This i planed and then sanded flat gently leaving no gaps at all to fill.


Posted: 18/10/2005 13:31:51
By: Jeremy3550
That's the way to do it without doubt.  Loads of clamps, a bit of ingenuity and a shedload of care to get the joints tight.  God! and Christ! are often invoked to help in boat repairs but do remember that Jesus still chose to walk rather than sail on the water!!!!!  Perhaps there are now Merlins in the afterlife?


Posted: 18/10/2005 13:38:19
By: Garry R
Various comments above remind me of my favourite quote, heard on this very forum years ago:

If God had meant us to sail plastic boats, he would have given us plastic trees.


Posted: 18/10/2005 13:45:40
By: Mags
Sorry for once again hijacking this thread, but..
Jeremy, I was most likely going to go for the Robbin Sapele ply (Tiger Elite I presume) Do you have any more pictures of the finished look? I've seen the one in the for sale section, but other angles would be good. Does the grain of this stuff make it hard to match when it is scarfed together on the side deck?


Posted: 18/10/2005 14:42:25
By: gb
It does have a very wavey grain and it could be difficult to match up. The grain patttern will vary though from sheet to sheet so yours may be easier. I do have some more pics and i will see if i can send you some.


Posted: 18/10/2005 16:07:47
By: Jeremy3550
Scott - I'm in the middle of redecking and deck-stepping MR 3285, a Bob Hoare composite NSM 2. I've been keeping a photo-diary of the project. I'm not an expert but have met some of the problems and have researched some of the solutions. If you care to e-mail me, we can arrange to talk and I can send you some photos.


Posted: 18/10/2005 16:46:49
By: Richard S
finished robbins sapele picture at http://www.littlejoesolutions.co.uk/merlin/prepainting.gif


Posted: 18/10/2005 16:48:07
By: wood
a big thanks to every one on the feed back the biggest problem that i see is trying to get the gunwales off and back on while trying to make any where near as good a job as Mr Smart the boat is totaly original and in very good nick other that the fact that half of one side deck the carling also the top half of the frame are missing!!!!
(the Gunwalls are intact and not damaged)
I have to say that I fancy taking longer in the marquetry route for an over all neater job. I recon that some 4mm MDF for templates, work at a sensinble pace and the boat will be ready for the Scottish Event by Easter.
If I try this method and it does not work out then I can pull off the gunwalls and start again without wasting good marine ply.

If any one has photos relevent to this subject I would be very gratefull for all assistance.

P.S. Your not out of the wood yet Garry I may call on you directly for more info.


Posted: 23/10/2005 20:04:36
By: scott 3072

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