that shows a sort of “t”
The other question that comes up here has to do with whether double hose clamps are required. ABYC does not require them but European standards do. So, on many boats that come from overseas or are built to their ISO standards you will see the double clamps. Interestingly, at least for recreational boats, the USCG is silent on the subject.
Hope that explains the situation. For those that have no idea what a p trap looks like, just do a quick web search. There are loads of pictures that show what a p trap looks like and explain how and why they work on the web.