This is approximately where the head will go the elbow is the outlet to the outlet sea cock and the the barb on the motor the inlet from the just below the sea strainer in the engine bay photo below
sea water level is just under the the bottom of the sea strainer which in the head photo would be at the macerator motor level
I intend to fit a a s/s T where the barrel fitting is and run a s/s pipe across into the head compartment through the fiberglass wall and then fit a ball valve for the inlet side of the head
The out let sea cock would be below and to side of the head in the direction of the elbow is pointing to a new hull through sea cock .
My question is .Should I fit a vented loop. on either or both inlet and out let hoses
I may fit a holding tank later .
Thinking about it a little longer I think I better vent both sides if used and left open while sailing I might run into a problem
So I'll sort it out and probably alter how the the macerator and inlet and out let of the head again
Answered my own question
I think Ill run a inlet vent at the inlet ball valve on the head compartment side of the engine bay wall and the out let on that rear head compartment bulk head
Question! why do you need to vent the inlet?
Can see venting the outlet, but I do neither,
My seacocks are always turned off and only opened to flush and then closed immediately.
That way there are no open seacocks to flood the boat.
That what I do always ,even after running the motor the same sea cock for the motor will also be feeding the head inlet the head will have its own ball valve running off just below the engine sea strainer
murphy's law
Usually every thing goes fine but when you have some one not so boater on board that's when some thing like a sea cock left open could