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[tigertiger]

I want to use ply to make decks on hulls for scale sail models.
The hulls will be in excess of 1m, I am even thinking of a 2m hull.
The beam will be in excess of 300mm possibly.

I have seen ply in sheets of 100 x 30 cm. So I am assuming I will need to make the deck out of more than one piece.
I will also be planking over the top of them, which may be harder to do after the deck is fitted, as it will not be flat.


What is the best type of ply to use for decking?
How thick?
Any advice on construction with several pieces of ply?

[RickF]

I am currently planking decks using 1/16" (1.5mm) sheet, followed by 1/16" bass or obechi planks of the appropriate width. Depending on the size of the model I use balsa or obechi as the substructure (usually 36"x 3" or 4", although larger pieces are available), suitably finished and protected. I have found that using one big sheet is wasteful when all the hatches and other bits and pieces are cut out. The only disadvantage is that there must be plenty of deck beams, but theses are necessary to preserve the deck camber anyway.

Rick

[dougal99]

I planked the deck of my Sea Queen with 1/16" obechi planks. The deck was in 6 pieces (bow x1, sides x4 and stern x1). The joins are butted on deck beams and the planks cover the obvious join lines. One problem I found was ensuring that the planks were all the same width, as even tiny differences can build up and you get different numbers either side of the centre line  :'( fortunately this doesn't show up (except to me)

Cheers

Doug

[Bryan Young]

Ply of whatever thickness will only curve in one dimension. i.e. you will not be able to get both camber and sheer on one piece.
You will need a false "underdeck" to which "camber" beams will be fitted. Segments of thin ply can then be fitted as a secondary false deck, and the "real" deck planks fitted on top. Sounds awful having 3 layers but it works and is strong.

[tigertiger]

Ply of whatever thickness will only curve in one dimension. i.e. you will not be able to get both camber and sheer on one piece.
You will need a false "underdeck" to which "camber" beams will be fitted. Segments of thin ply can then be fitted as a secondary false deck, and the "real" deck planks fitted on top. Sounds awful having 3 layers but it works and is strong.

Hi Bryan
Never having done this I am having trouble seeing it in my minds eye so to speak.
Can you give some pictures or a sketch please?

[tigertiger]

Hi Bryan

To be a bit more specific,
I understand why the ply will only bend in one plane.

It is how the three layers sit in relations to each other, that I am not clear on.

[John W E]

Hi there TT,

You could try scoring the back of the plywood you are going to use for the decking at equal spacings across the grain of the first veneer (just breaking through the first veneer).   The sticking it in a bath of hot water for about 20 minutes allowing the plywood to soften and then sticking it on using heavy weights.   If you have access to liteply, this bends in both directions quite easily.   If you have a look at the decks on the Cervia build, you will see that is what I have used on there, because that has a fair rake and a fair camber at the bow.

For normal decking I use 1/16 modelling ply.   I have also decked a model using several pieces of plywood and I staggered all the joints, but, I commenced on the middle of the model working out towards the ends.

aye
john e
bluebird

[Bryan Young]

Hi Bryan

To be a bit more specific,
I understand why the ply will only bend in one plane.

It is how the three layers sit in relations to each other, that I am not clear on.

Sorry Tiger, missed your query. 3 layers.  A flat deck that sits inside the hull, thick enough to do the job you want. Mine range from 0.25" (big models) to 1/8th" for smaller and lighter boats. On the flat deck I fasten the camber formers (normally cut out of 1/4" sheet) in positions dictated by deckhouses, hatches etc. The 2nd layer is the thin ply sheet (1/32 or more usually 1/16th") which overlaps the flat deck to the edges of the hull and is fastened by all sorts of ways to the camber formers. Then plank on top of the thin ply. This method may not suit many, but as I believe in having maximum access to the interior of the hull the decking and superstructures tend to come off the hull in long lengths so I need rigidity. I also brace the underside of the decking as described elsewhere on the Havelock postings. Hope this helps. Cheers. BY.

[tigertiger]

Thanks for the input everyone.

I now have a clear idea of several methods how decking can be achieved.