Let's get nibbing!
First off - why nib? Well, cut ends of planks are fine up to angles of about 45 degrees. More than this, and the wood develops a weak point at the "sharp end" where weathering can occur. To avoid this, the sharp end is cut short, and the resultant joint is let into the edging. The trick is to have at least one perpendicular cut halfway across the wood, and make sure both cuts match the angle required by the outer edge of the edging wood they're jointing into.
Here's a plank that needs nibbing at the fore end of Y barbette. (The barbette will fit within the edging piece, over the curved red line.)

Holding the plank over the edging, and knowing the half-width of the plank, it's easy to cut the correct angle into the plank. Then holding the plank over the edging, it's clear where this has to be cut to fit.

The joint angles look good!

Now trim the other end of the plank to suit the deck - you can just see here that there's a quarter-length joggle per plank run. That giant pound coin is to make my woodwork look good. (Nah...it's really 22.5mm in diameter - the plank lengths are four inches, the width 3mm and the thickness 1mm. I'm using lime strip, as per Ron's lovely Iron Duke.)

Apply glue and get the caulking ready - this is standard polyester thread, cut a few inches over the length of the whole plank run; here that's the gap between barbettes X and Y, containing two full planks and a couple of shorties.

Offer up the plank, leaving a small gap, and lay in the caulking along the long edge. Once again, PVA is wonderful glue for this - you get under a minute before you know it's too late, but that's enough time to shuggle the pieces, apply the thread, swear once or twice, and finally see it home.

Run the thread...

...around the joint...

...and scrape off any excess glue with a plank specifically used for the purpose. Then work your way along the plank lengths (I go from right to left, as I'm left handed.) and prepare the other end - once again, joint first, then trim the plank to length. It saves trees.

Finished! Now the thread ends are trimmed off, and the next plank run can begin.

For caulking, I'm using two indispensible tools. This is handy and always available...

...while this one is the blunt end of a tiny scalpel. The caulking wants to lie just below the top of the plank as these will get a light sanding before being sealed later. Any fluff on the thread tends to get glued in during the process, and will certainly be taken care of when the varnish/sealer is applied.

Here's a close-up of the first three nibs at the barbette. Florian, the blue guy, is still 25mm tall.

Hmmm....I've a way to go. But the effect is lovely, and from certain angles (though not this one) the plank breaks are obvious, aided by subtle changes of wood colour and the regular pattern of overlap.

I reckon I've done 150 sq cm in about three hours - so 100 hours should see the decks covered. That may sound like a lot of work, but given the amount of deck on the ship, and the effect it'll have once done, I think it's justifiable.
Regards!
Andy