[HO455]

It was a beautiful day so I got busy making sawdust. The plywood I am using is a marine plywood with non-skid coating material on the top bottom and sides. This means only the places I cut will not be coated. Not the cheapest material but it showed up on Craig's List so I went with it. I think that better quality plywood (no voids) is out there but I'm not sure if it would be better in this application.
The plywood came in 4x8 sheets so i will have to join two pieces together to make the floor. I went back and forth in my mind as to where to put the seam. Eventually I decided to put the seam as far to the driver's side as possible. Several factors lead to this decision. One was if the floor gets point loaded by something like an engine block being dropped, an unseamed area should withstand the load better than an area with a seam. The center of the floor is the most likely place for something like that to happen. Then as a secondary advantage it will be easier for me to fit up the driver's side cutouts if I'm not having to test fit a piece that is 3 foot wide. And lastly having a larger piece left over will let me use it for some steps on the front porch. So good decision or bad decision only time will tell.
After lots of measurements to make sure I didn't make myself angry right off the start I did the easy cut first. (Photo #1) Since the wood is coated on all sides I had to make a skim pass with a router on one of the long edges to make sure that the seam will have clean wood for the glue to adhere to.
Then I laid out the dimensions of the piece I just cut on the old floor piece. Once it was laid out. (Photo #2 silver line on old plywood) It was fairly easy to get the dimension of the smaller piece for the driver' side using a straight edge on the few remaining spots that had not rotted away. After cutting the smaller piece I clamped it under the old floor so I can do the layout for the wheel well and fuel fill. As you can see there is a lot of wood missing. (Photos # 2) Most of the missing areas were swept up after removal. It just fell into dust and splinters.
In order to make the wheel well I traced the one good end on to some corrugated plastic and cut a pattern. (Photo #3) Then I flipped the pattern and drew the outline on the new wood. (Photo #4)
One side note the coating material on the plywood is quite rough and hard to make pencil marks on. It just eats the lead on the pencil so the line gets fatter the farther you go. So the line is not very accurate. I tried scribing lines but found that it was difficult to see the line and even more difficult to make the scribe stay on the straight edge. I ended up using a fine ball point pen and going slow to get a reasonable line.