I have a CT41, and am a member
of the owners group (LeakyTeakyYachtClub on Yahoo groups) as well.
I don't have your problem (but I've had plenty of others). One tool that I found incredibly worth the $$ is the Fein Multimaster......you can set the depth
of cut, and that way guarantee you'll cout only through the floor and not a support beam. I realize this isn't helping you to figure out your solution, but once you have, at least there's a tool that will keep you from doing too much harm!