This isn't remotely close to anything recreational but it is pretty cool. I had a business associate who long ago took a 75'-ish Hatteras, sectioned in 20' and added a third engine (with a jet drive for quiet slow cruising and increased maneuverability) :
http://sploid.gizmodo.com/watch-cruise-ship-get-cut-in-half-and-made-99-feet-long-1510151277
http://sploid.gizmodo.com/watch-cruise-ship-get-cut-in-half-and-made-99-feet-long-1510151277