Forums: Whisstock Designs: quantity of plywood needed New Topic Post Reply
Author Post
dozigman
Posted: Apr 18th, 2011 at 18:44   |   Subject: quantity of plywood needed
The specification sheet for the 055 does not seem to include amount of ply sheets needed for planking (or decks for that matter). Since I k now the strakes are a multi-curve config., I don't know how to estimate. Can this be known? Am I missing that on the spec' sheet? Thanks.
debenriver
Posted: Apr 18th, 2011 at 21:22   |   Subject: quantity of plywood needed
There isn't a bill of materials included in the design data, but I can work out the approximate quantity of ply required.

I will come back to you on this.

George
dozigman
Posted: Apr 22nd, 2011 at 15:06   |   Subject: scarfs?
concern is whether the 055 requires more than 2- 8 foot lengths of ply for the strakes? we may seek out 10 ft. pieces if that is the case. what do you think?
debenriver
Posted: Apr 24th, 2011 at 07:59   |   Subject: quantity of plywood needed
The base quantities of ply for the design should be follows:

Planking 9 sheets 2440 x 1220 x 9mm
Deck 2 sheets 2440 x 1220 x 6mm

The transom can be a single piece of 18mm ply, or two layers of 9mm ply (which makes getting the edge bevel easier). If you make it from 9mm ply, and add in the ply for the centrecase and you will need 2 further sheets of 9mm ply – making 11 in all.

Most of the planking will come from scarphing together two full 2440 lengths of ply. However I think the sheerstrake and the next plank down are not quite going to come out of two 2440 lengths scarphed together.

A skin expansion for this design is in the works, but not imminent. This will provide DXF files for CNC cutting of components, plus dimensioned drawings for the developed shapes of the planks.

You can scarph 9mm ply sheets together (to form a single sheet 4800 (less the scarph length) x 1220, or you can scarph the individual plank parts together. If you were able to source two of the sheets as 10' sheets, then you would be sure of getting all the planks out with a single scarph in each.

The instructions are written on the basis that each plank is scarphed up individually, because this is usually the most convenient way to handle the plank lengths with a limited number of people. Doing it this way you can stagger the scarph joints, which always seems a nice thing to do, although if you accept that the scarph is as strong as the plank, then there is no structural reason to do this!

Either way, a Gougeon Scarpher attachment is a good investment with regard to time and quality, and make the job fairly straightforward.

George
dozigman
Posted: Apr 24th, 2011 at 12:00   |   Subject: thank you
I imagine it is a fair amount of work to calculate the quantities. Your 055 builders appreciate it!
debenriver
Posted: Apr 24th, 2011 at 17:31   |   Subject: ply quantities
It's not so much the work involved – it's really the fear of being wrong! I have no fear of being wrong when I am designing or calculating structures, or anything else to do with the design and construction of the boat. But the thought that I might make someone buy one sheet of plywood too much (or indeed too little) seems daunting to me .... which is not really rational at all.

So here's hoping I am about right!

George