Sorry but not ALL unit have a P-Trap under the bathtub for what I know. My 24RBS have what they call a waterless trap. Its like a rubber membrane .hummmm best exemple would be like a baloon open at both ends. When there is no water the baloon remain flat blocking stinky smell , when water passes the baloon allow the water to pass and collapse right after....sorry for my frenchglish....try googling for waterless P-trap.
Jayco Whitehawk 24RBS 2014
Ford F 150 Ecoboost Tow Max 3.73 2014
Equalizer hitch 1000/10000