Here's one picture that's not really illustrative of the bottom planking process:
The bottom planking process is only as successful as the fairing of the keel, chine, battens and frames. As described in the instructions and plywood boat building book, you can most easily accomplish the fairing by using strips of plywood ran from the keel to the chine, using this as a guide to determine where material needs to be removed. This is a somewhat slow process, but it becomes easier over time, because you can fair at the frames and then adjust things as necessary between the frames. I can't stress this enough - spend a good amount of time and get the fairing right before you ever touch the plywood planking. The work became somewhat meditative, especially as I got better and better with planes.
After I did as much fairing as was reasonably possible, I got out the plywood. Because I am using 8' plywood sheets to plank a 14' boat, I would need four pieces of planking: two each fore and aft, on either side of the keel. The two aft pieces each required one sheet of 4' x 8' plywood; the two fore pieces were taken from one sheet of the same.
When my folks came down, my main goal was to get the planking pieces rough cut. A full sheet of plywood is too much for one person to work with for any amount of time, and since I do a lot of this work by myself, I wanted to make it manageable. So dad and I rough cut the aft pieces - the picture above is during part of that process. After rough cutting them, we spent a good deal of time getting them fit for length, as well as working on the fit around the centerboard case. We worked the plywood a little bit at a time, which was the only way we could ensure a tight fit. Yes it's slow work, but there was really no other option. Because of the way the bottom angles down toward the transom, it has to be sprung into place - this springing means that the planking will actually be a bit proud if you were to lay it on top of the transom. That's why you have to go slow and remove material in small amounts. As it turns out, we got the port side piece almost perfectly fitted, and the starboard piece was pretty close. (It just needed a little additional work, which I did after my folks left.)
Compared to the aft planking, which lies somewhat flat on the boat, the fore planking requires a lot of working before it's fit. The main reason for this is that there are two transition points - one point is on the chine, where the planking moves from a lap joint (aft) to a butt joint (forward), and the other is at the stem, where the planking moves from a butt joint (aft) to a lap joint (forward). Here's what I'll say about these joints - I chose these points somewhat arbitrarily, based on the instructions and the book. I placed the chine transition point halfway between frames # 3 and # 4, and placed the stem transition point just forward of the transition point between the keel and stem. I spent a lot of time thinking about the placement of these points, only to realize that I should just pick them and move forward. I suppose you could get philosophical about these choices, but it's a boat, not a painting. Get it done.
For the forward bottom planking, I first fit the port piece in place and glued it in. I used the chalk method of transferring the line of the side planking onto the bottom planking. (I used sidewalk chalk - you can get a box of this for $1 at a craft or office supply store.) I was first afraid that the plywood wouldn't bend sufficiently, but it took the curves with no problem. When I glued and screwed the port side forward bottom planking in place, I made a mistake. I started at the bow and placed a screw at the 'point' of the planking (e.g. the most forward point of the planking), and then moved back, placing screws alternately in the stem and chine. When I got to the end of the piece of planking, it turned out that I had a gap of 1/16" along the chine. The reason this gap appeared, I think, is that I didn't properly secure the forward part of the planking before moving back. In addition to the screw at the very forward end, I should have also placed a screw in both the stem and chine, 8 inches or so aft of the point. (I had already drilled out these screw holes when I was dry fitting the piece, and could have simply driven the screws at that point. Turns out, I should have done that. I think I ended up 'crumpling' the piece of planking much like you might crumple a piece of wrapping paper. The distortion wasn't huge, but it was enough to leave a sizable gap along the chine which will now have to be filled with epoxy filler.)
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