Paul Gartside 18' Racing Gaff Cutter • Cabinversion designed by Dominik Gschwind

2012-11-18

Week 16/17 - Laying deck

I don't know what it is but laying a wooden deck seems to be one of the most fascinating tasks during the built of a boat for most of the people.

However, all starts with a fullscaledrawing of the layout on the boatsubdeck.
My design included bent deckplanks parallel to the sheer and ending with snapes into kingplanks at the bow and stern.
Tests with 40mm wide planks of 8mm iroko showed that this was impossible just by bending. The curve and the bow was too much.
Laying the planks just straight fore and aft was no alternativ for me.... just not satisfying. Glóey's lines needed something more dynamic and elegant!
Well, the solution consisted in a compromise which included that the deckplanks were bent parallel to the sheer along the cockpit and from the portholes towards the bow they just run further in a similar curve (meaning less narrow radius than the sheer) and snaped into the coveringboard.
The photo beside shows that princip in more detail!
The marginplank along the cabin and cockpitcoamings was sawn to shape as well as the finally fashioned covering board (see further down).

Iroko is an alternative timber to teak which has relatively similar properties but is much cheaper. Same as teak it also is very oily by nature. An aspect which on one hand makes the deck very durable in use and on the other hand has to be degreased and cleaned with acetone before glueing with epoxy.
The iroko we used had a lot of tension in the material... came very likely from a bent tree!
This resulted in deformations after sawing (even cracking while sawing on the bandsaw occured!).
However we finally got a feeling for that exotic timber and managed to lay the deck relatively accurate.
The pictures show in detail how the deckplanks are held in place while glueing them on. We've choosen washers and screws which could be used along the beams and halfbeams of the deckframing.
Minimal adjustments in the width of the planks allow unvisible corrections of slight asymmetries in the deck.
There is quite a lot of work left when finishing the plank glueing!
First all the holes of the previous mentioned screws had to be filled with epoxy (use of syringes) and all the visible bare plywood in the seams had to be sealed as well (see A in photo).
I didn't mention that the seams first had to be cleaned of all epoxy excess.
After sealing the seams were slightly sanded to get both a nice surface and the amin off from the epoxy.
B in the photo shows that both sides of the seams had to be primered (SABA marine primer) to get a better bond on the iroko.
And finally all bottoms of the seams got taped with a special green breakertape (C in photo). This avoids the caulking to bond to three sides because a seam between 2 sides has much better properties and therefore longer lifeexpiry.
Now it was time to fill the seams with SABA Caulk.
That flexmaterial is applied with guns and is a moisture curing caulking. It takes 24 hours for 3mm of SABA Caulk to cure. With other words we had to let the whole caulking go off for arround a week before sanding.
Some days after we've cut all excess of and did refill some voids in the caulking and after waiting another 3 days it was time to get the whole deck finished.
The mainjob is to sand with 80 grit to get everything down flat and nice without producing lowspots.

And yes.... wow... what a look and feel!