What is this valve for?

[HappyPlace]

I was recently cleaning some vents and exploring some of the compartments on our 2014 R31, when I came across a closed valve behind the aft stateroom on the port side. Preliminarily, I can see that it goes to a thru hull fitting on the port side and the hose further back it is attached to a pump. The factory build sheet I obtained, indicates we have a macerator, so I am guessing this may be part of the discharge. Also, does anyone know where would I locate the Y valve and macerator on this boat? I want to make sure is it closed and secured properly.

Thank you in advance,

 

[Irish Mist]

That would be your macerator valve . The pump is the macerator. There will be a switch on the panel to activate it, The valve eliminates accidental discharge. As far as I know there is no "Y" valve . Hope this helps

 

[Cessna172]

It is my understanding that you can acceptably secure the type of valve in your photo by simply removing the handle while it's in a closed position.