I constructed the coaming recess in the last post, now the trick is to install it in the boat. I start by smoothing the deck a little by giving it a quick scraping. This just makes it a little easier to mark the hole. The plans for the Petrel include a pattern for marking the hole. I cut this out, right on the lines. The pattern has marks indicating the location of the forms as well as the feature lines. I pre-crease the pattern on the feature line marks so the pattern will sit better on the deck. I align pattern with the forms, feature lines, center line, and sheer line and then use a pencil to mark the location.
I use a pull saw and jigsaw to cut out the hole. I left about 1/8" proud of the line all the way around, just to leave room for errors. The recess assembly I made previously was also cut about 1/8" oversize. I will need to deal with the extra eventually.
There are a myriad of tools that can be use to work on the edges. In this video I use a chisel, sandpaper on various blocks and sticks, planes (the Veritas® Side Rabbet Plane is very slick), and rasps. The goal is to work down the edges of the insert and the hole such that the match up with a good tight fit. I start by planing the edges of the recess assembly and then work on the edge of the hole. I start at the front where there is less flexibility and move backwards. I pay attention to assure the recess stays centered on the deck at the front and the back. As I get a tight fit, I find that pulling a thin piece of fine sandpaper through the slit does a good job of fine tuning the fit.
When everything fits tight, double check with a dry-fit all taped in place, add glue and tape it tight.
