Y - valve schematic...

[k. michael marquardt]

Originally Posted by Cheechako

Then this one has a pointer, but the handle kinda goes with a flow possibility too... "what do dat do?" Is the flow with the pointer and one end of the handle? Which end? Or with the handle only? If so, what is the pointer for?

The handle shows the flow in your pix. What you call a pointer is a tool to secure (plomb) the handle so it cant be turned the wrong way (That's why there ia the hole in the 'pointer'. Some authorities will do that to prevent discharge of raw black water directly to sea without using the holding tank.

[Cheechako]

Still... you have to admit the damn things are confusing as hell!.... as well as really cheaply made.