Don't use rubber back carpet or carpet tiles on the cabin of a boat. That rubber won't hold up well to a marine environment and if you ever want to replace it, the rubber will be a major PIA to get off the floor. You will be scraping rubber until your arms fall off. Also, for a glue down installation, you don't want to use the old carpet as a pattern. For this type of installation, I really don't use a pattern. I measure the length by the width and add 6 inches and cut my carpet to this size. I lay it in dry (no glue) and rough cut it so it lays nice and smooth. Then fold the carpet back half way, spread the glue with a notched trowel and lay the carpet in to the glue. Fold back the other half, spread the glue and lay down the carpet. Then final trim everything. Only use very sharp blades. As soon as they dull, change them. Try not to leave any raw edges of the carpet exposed, it will eventually unravel. BTW, the strongest fiber is nylon. Olefin supposedly holds up better to the uv, but will eventually mat down. Just look at your cockpit carpet. All the traffic areas are matted down as compared to the non-traffic areas. If you can get the boat to Long Island, I'll help you with it.