Yea, we have a lot of rules, man. Like if every boat did this in a port, it would be really unsanitary, so there's rules about when and where you can pump, but it all goes into one of three types of holding tanks, then pumped based on where we are, gray water can't even go overboard in Port because of detergents and soaps. In fact a type 1 marine sanitation device (also known as an MSD) with vacuum lines, the same overboarding centrifugal pump used to overboard, has valving and guages that run the poo water through whats known as an educator to build vacuum, we keep cigars on board just for finding vacuum leaks.

Marine engineers are a strange trive because of limited people on the boat, we have to be plumbers, electricians with power generation knowlage, diesel plants, boilers and in order to be competent were HEAVLY trained. I'm sure I'm just tooting my own horn but I like to think of us as maybe special forces of the trades, licensed in all and when we're not on the boat, we're always training, electronics? Networks.

It's dangerous to go deep sea and not have spare parts and rigorously trained engineers.