Head inlet / Outlet seacock placement and plumbing

[MarcoP]

Hello all,

I closed my 1 1/2" thru hull previously used for head discharge, originally planning on installing an air head and no longer using a marine head. However, I now find myself in the possession of a brand new 1 1/2" seacock and new marine toilet and am considering installing those instead. However, if I do drill another discharge thru-hull I am concerned about having it far enough from the inlet thru-hull so I'm not recirculating poop around, as Don Casey recommends in This Old Boat (the original ones were less than 1ft apart under the head sink). As a way of keeping the seacocks far from each other, Casey recommends plumbing the head inlet to the galley sink drain "if it's on the other side of the hull." That is not the case in my Valiant 32. Since the seacock-friendly space in my head is so limited, I am now wondering "how bad can it really be?" Maybe I'll just do some extra flushing or throw some fresh water on the bowl at the end of the flush."

Do you have any suggestions on how to proceed while keeping odors at a minimum? Why is a galley sink drain + head inlet connection if they are on opposite sides of the hull? If I end up doing that, would I be able to also use the same seacock for the head sink drain and the head discharge? Lastly, am I right in assuming both seacocks next to each other isn't the end of the world?

Thanks!

[Manateeman]

Water is not the only thing going down the sink drain. Food and grease combine to form yucky blobs that require boiling water and a stick to clear. Sink drain straight down and straight out the hull. Attaching the head inlet or washing machine outlet or shower water outlet or bilge pump outlet...is asking for problems.
Head DISCHARGE into sink discharge.? No no no.
Even with a light current, the brown cloud will be carried away. I’m assuming you are NOT doing this illegally. Please give the manatees a break. A fresh water rinse is nice but please don’t connect your head to your water tanks.
Happy trails to you.
Mark and his kissable manatee crew.