The machine should be capable of sewing through several layers of canvas. Most of the sewing will be through 2 to 4 layers of canvas, but some seams and finish work stitching is through more layers. Pull the dinghy out of the water and give yourself plenty of room to work around it on all sides. You'll be working both inside and outside of the inflatable so make sure to stabilize it. A newspaper or roll of brown wrapping paper.
Newspaper is easier to work with, but wrapping paper is more durable.
A good pair of Scissors. The idea is to construct a cover out of paper that Simulate a finished product and pretend the paper is the real thing. You'll be taping the paper directly onto the tubes. Start at the bow with a full page of newspaper or a large piece of wrapping paper. Drape it across the tube and tape it where you want the finished edge of the cover to terminate on the outside of the dinghy.