Hale, If you are looking for a porta potti (Thetford model) for the M15, you will need to stick with the Thetford 135. This is the model toilet that Jerry was using when I designed the M-15. Unfortunately, Thetford changed the dimensions slightly and never contacted Jerry for authorization to change the design. (tongue firmly planted in cheek). Jerry wasn't about to change the M-15 molds, so the quick and easy solutions to make the new Thetford 135 fit your M-15, just add hot water and 2 beers!! Let me explain. Place the Thetford 135 in the well for the porta potti. It won't quite fit, so you will have to add several gallons of hot (boiling water) into the storage tank and sit on the porta potti to assist in remolding the base to fit the well. This is where the 2 beers come into play. Once the water cools, you will have a perfectly formed Thetford 135 for you new M-15. I hope this information is helpful. Skip M-15 #201 'Wild Guppy' M-10 #177 'Lil' Guppy' -----Original Message----- From: Hale Irwin <hale.irwin@comcast.net> To: montgomery_boats@mailman.xmission.com Sent: Fri, Mar 25, 2011 1:50 pm Subject: M_Boats: Porta Potti 365 MSD - Portable Marine Toilet Does anyone know the 3 dimensions of the space for a porta potti in the new ontgomery-15? The Thetford 365 would be ideal if it will fit. It's dimensions are: Height 16-1/2" : 41.9 cm Fresh Water: 4.0 gal: 5L WIDTH 16-1/2" : 41.9 cm Waste Tank: 5.5 gal: 21L Front to Back 15" : 38 cm Will this fit? emper Fi, ale ale.irwin@comcast.net ______________________________________________ ttp://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats When posting, remember that there is no privacy on the Internet!