I have a 2016 Sunseeker on a MBS chaises. On my last trip my shower was draining real slow. I checked and saw a piece or rubber in my drain. I took off the access panel in front of my shower pan to get at the trap in my drain so I could take it apart and get that piece out. Surprise no trap. So I proceeded to dig out the piece of rubber from the drain. After looking at it I came to the conclusion that the piece of rubber was part or a (want of a better word) blather that opened to let water drain and close after. Anyone else have had this problem. Now I a get the smell from the gray tank, which isnít to bad, coming from the drain.
I think what you have is a destroyed one of these:
HEPVO 1-1/2 TRAP https://www.amazon.com/dp/B00NLMPLDU..._WytNBbDQ92H85
On new units that have these waterless P-Traps, there is a warning sticker on the shower base that reads: Do not use routers to clean the pipe.
So if your drain gets plugged with hair, soap or “other” debris, you have to disassemble to clean it.