Can you identify these pipes?

[Brian Schulz]

Hi there, new to the forum, just bought an argosy 26 and summarily removed the interior, cleaned, and painted with plans for a whole new setup.

Now one part of the old setup was this ABS vent tree in the back right corner that appears to belong in an art gallery. Kudos to the guy who built that crazy thing.

Three pipes coming out of the floor. Blackwater vent, gotcha. Greywater vent, makes sense. But what is that third pipe next to it? Anybody got any ideas? I've got a background in the trades and I've noticed that sometimes people get a bit zealous when they're not quite sure how all of it works. But before I cap one of them off I want to make sure there isn't a point to that third mystery pipe?

Any ideas? THanks!!

[xrvr]

Shower vent, my Avion has one. Jim