how does the toilet work

[SolentPhill]

Ive been helping a friend with a new boat today its a 2nd hand one 3 yrs old and it didnt come with much paperwork, im trying to work out how his toilet works, mine is simple and makes sense but his confuses me so can someone explain please.

He is on the hard standing, we had a hose working today and he wanted to flush out his toilet, he does not have a holding tank, but when we put the hose down the toilet the hose water came straight out under the boat, I guess there must be a valve to stop sea water coming up from the sea, he has a macerator fixed to the back of the toilet with a switch in the bathroom. the inlet and outlet at the bottom of the boat are about a foot apart, I take it water from the sea sits in the toilet, that must make it dirty. and as the inlet and outlet are next to each other whats stoppping what you flush coming straight back in?

 

[Elessar]

Ive been helping a friend with a new boat today its a 2nd hand one 3 yrs old and it didnt come with much paperwork, im trying to work out how his toilet works, mine is simple and makes sense but his confuses me so can someone explain please.

He is on the hard standing, we had a hose working today and he wanted to flush out his toilet, he does not have a holding tank, but when we put the hose down the toilet the hose water came straight out under the boat, I guess there must be a valve to stop sea water coming up from the sea, he has a macerator fixed to the back of the toilet with a switch in the bathroom. the inlet and outlet at the bottom of the boat are about a foot apart, I take it water from the sea sits in the toilet, that must make it dirty. and as the inlet and outlet are next to each other whats stoppping what you flush coming straight back in?

nothing. That's why the inlet must be forward of the outlet.

 

[Wiggo]

I guess there must be a valve to stop sea water coming up from the sea, he has a macerator fixed to the back of the toilet with a switch in the bathroom. the inlet and outlet at the bottom of the boat are about a foot apart, I take it water from the sea sits in the toilet, that must make it dirty. and as the inlet and outlet are next to each other whats stoppping what you flush coming straight back in?

Well, first off, the bog should be installed above the waterline, otherwise it could all go horribly wrong...

Second, there will be a pair of seacocks on the inlet and outlet pipes, so if you haven't found 'em, go take a look and make sure they work. The time to find that they break when you operate them is now, with the boat on the hard, not when you're out at sea.

Third, yes the sewater is 'dirty' in that it contains bacteria. When you leave the boat, they will die in the inlet pipe and as they break down they produce the characteristic rotten egg smell you get when you first flush the bog after being away for a while.