Sewage pump out query

[Tim O]

I’m a liveaboard and because our marina closed it’s facilities due to the lockdown I’ve been using the onboard heads and holding tanks.

The time has come to pump out and I’ve not done this before... the output from my tanks has a manual Henderson pump then a y valve diverting waste either to the deck waste and hence to pump out station, or to Blake’s seacock for discharge at sea.

I presume I’ll have to attach the suction hose from the pump out station, switch it on then leg it below and start pumping....obviously having switched y valve to go the deck waste outlet???

Is this doable single handed or do I need someone to hold the suction pipe on to the deck outlet???

Presume I should also check the tank breather pipes are open to allow air in so the tank doesn’t implode!!!

 

[PilotWolf]

Why not switch to deck put hose in and then go and start pump?

W

 

[prv]

The pump-out station has a dirty great pump in it already - clue’s in the name . You shouldn’t need to be waggling your little handpump to assist it.

Normally a deck pump-out would come straight from the tank, no valves or pumps - you’re sure it’s plumbed as you describe? If it is, I would just wedge the handpump in whichever position has the diaphragm raised away from the pump body and let the shore pump suck through it.

Big yes on checking the breather.

Pete

 

[LadyInBed]

Big yes on checking the breather.

I think that the breather might not give the flow rate for a suction pump out. If you have a service / inspection hatch in the tank, I would undo that.

 

[PilotWolf]

I think that the breather might not give the flow rate for a suction pump out. If you have a service / inspection hatch in the tank, I would undo that.

I don’t know how big the breathers were, but we used to pump out the water taxis without an issue.

W.

 

[jtwebb]

The Y valve should indeed be before the manual pump which would go to the sea outlet. Those Y valves have a tendency to crud up and become immovable, they need regular exercising. I have fitted holding tanks to two boats, a Fulmar and a Dehler 36 CWS. In both cases I had two outlets on the tank, one to macerator pump and other to sea. In addition, I had a Y valve to divert the toilet straight to the sea in case of tank problems but they were never needed. I made sure the breather pipes were big enough.
Edited additions:
The pipes used in the Fulmar were:
8mtrs of 38mm Sanitation hose.
5mtrs of 19mm Sanitation hose.
A 1 x LS02070 Microvent filter kit was put in the breather pipe to trap smells.
I also fitted a flush pipe, 19mm, to another deck fitting so water could be poured in to flush the tank, even as it is sucked dry.
The 38mm pipe was the standard size for toilets and went to the tank and outlets to seat and macerator pump inlet. The 19mm was used from the macerator outlet, for the breather pipe and the flush pipe.

 

[Tim O]

Sounds like this system has not been set up optimally as the pump is definitely before the Y valve....it’s a big y valve. I’ll post pictures later.

Silly me of course the suction pump can pull stuff straight through the hand pump!?

The breather pipes are quite large bore...I’ll measure later and they run aft and exit through a skin fitting just above the waterline. I’m slightly concerned ncerned there is a one way valve on there which will allow air out but not in!! think I’ll disconnect it to be sure!

 

[jtwebb]

A friend of mine had to have a deck outlet fitted to his existing tank and the bloke who did it simply put a Y piece in such that the suction went onto the manual pump. In Holland at first pump out of a full tank the manual pump reversed it self and somehow stopped the deck pump outlet from working. I can't remember why but he was left with a full tank that he could not empty! As I said earlier, I had two independent pump out fittings on the tank.

 

[Bilgediver]

I’m a liveaboard and because our marina closed it’s facilities due to the lockdown I’ve been using the onboard heads and holding tanks.

The time has come to pump out and I’ve not done this before... the output from my tanks has a manual Henderson pump then a y valve diverting waste either to the deck waste and hence to pump out station, or to Blake’s seacock for discharge at sea.

I presume I’ll have to attach the suction hose from the pump out station, switch it on then leg it below and start pumping....obviously having switched y valve to go the deck waste outlet???

Is this doable single handed or do I need someone to hold the suction pipe on to the deck outlet???

Presume I should also check the tank breather pipes are open to allow air in so the tank doesn’t implode!!!

The deck pump out connection goes straight to the holding tank and the pump out station has a vacuum system the nozzle of which fits your deck connection.
It is not normal for the y valve to connect to the deck pump out station as normally it goes to a shipside connection to allow pump out at sea.

 

[ashtead]

Presumably if you are in a marina the staff might know what’s required? In my one experience of using the marina staff just attached the pump to the deck mounted screw cap and turned on machine ?

 

[prv]

I’m slightly concerned ncerned there is a one way valve on there which will allow air out but not in!!

Wouldn't that prevent you pumping the tank out to sea, which presumably you've done plenty of times (before you got stuck in the marina)?

Pete

 

[prv]

Presumably if you are in a marina the staff might know what’s required?

They aren't going to know the details of the OP's unusual plumbing system.

Pete

 

[ashtead]

But presumably limited choices for the marina staff ? If one way doesn’t work try the other surely ?