I have a Force 10 like you describe. That T-pipe is some sort of temperature control. FYI mine stopped working after a while and I called the company only to be told to bypass it ! So if the Kuuma fits without major alterations to the boat or the plumbing lines you can install it. And if you're worried about the temp, you can install a temperature control valve. They make them in 1/2 inch and they're not terribly expansive. There were some posts about them on this site not too long ago. Good luck with the install of the new water heater.