Heads and Holding Tanks

pinayreefer · #1 (**permalink**) 07-28-2011

Okay, so I'll admit that most of what I know about some systems on boats I learned from "This Old Boat" by Don Casey. In it he shows three different configurations for head systems on sailboats. Mine seems to have a third, that doesn't make much sense, is broken and I'm not sure if I should reconfigure.
First there's a holding tank, on one side at the bottom off which there is a bulkhead with a 1 1/2" fitting with flexible pipe that runs to a diaphragm pump (Gusher, I think). Out of that another pipe runs to a Y-valve, one side of which goes up to the deck pumpout fitting, the other side of which goes directly to the thruhull fitting overboard. Sound right to you?
From the toilet, the discharge goes into a 1 1/2" flexible pipe to a vented loop then directly to a bulkhead on the high side of the holding tank.
So when I set the Y-valve to pump overboard (3 miles out to sea) I pulled on the pump handle and got hosed with holding tank fluid (the nice way to say it). Seems there's a problem with the pump, but how to pump out the holding tank from the deck fitting? None of Casey's configurations had the pump between the pump out fitting and the tank. Aaaargh.

cb32863 · #2 (**permalink**) 07-28-2011

Not that I can help you but, you are going to be asked this question by anyone who can..... Do you have pics and/or a diagram you can post? That sort of visual information is very helpful.

CB

treilley · #3 (**permalink**) 07-28-2011

That is actually a pretty common setup although the Y should be between the tank and the pump. The pump out through the deck is done via shore-side pump-out pump. Suck everything up through the hose providing your vent is free.

Make sure the thru-hull for the discharge line is open. The gusher is a great pump but the seat to the valve will corrode and it will stop working. You should be able to get a rebuild kit if the seats are still good. Otherwise you will be replacing the pump. Also make sure the duck valve in the output flange of the toilet is good.

More good info here: http://www.ericsonyachts.org/infoexc...head#post37039

pinayreefer · #4 (**permalink**) 07-28-2011

Seems that trying to vacuum out the tank through the deck fitting would get stopped at the check valves on the diaphragm pump if it's working right, and since it's leaking, would suck in air. The previous owner confessed to never having done dockside holding tank cleanout.
Will pumpout work? I ask because the tank is nearly full and the pump is fritzed and I'd like to keep crap out of the boat!

CaptainForce · #5 (**permalink**) 07-28-2011

I can't say that there is only one right answer, but simple usually trumps. I pump everything to the holding tank with no Y-valve........

'just a T fitting after the tank will allow pump out or a macerator pump to overboard depending on your location. I have no Y-valve, but the locker to my through-hull is locked and the handle has been removed while the through-hull is left in the closed position. This is in full compliance and remains simple. Take care and joy, Aythya crew

HPLou · #6 (**permalink**) 07-28-2011

The hose from the holding tank should go to the Y valve. One outlet of the Y valve should go to the deck fitting and the other outlet should go to the pump which then goes to the thruhull discharge.

SlowButSteady · #7 (**permalink**) 07-28-2011

If you ever replace the holding tank, I would suggest that the outlet be relocated to the top of the tank, with a dip-tube extending from that fitting to about 1.5 inches from the bottom (on the inside of the tank, of course). That way you never have any bulkhead fittings with any fluid pushing against them.

tdw · #8 (**permalink**) 07-28-2011

Quote:

Originally Posted by pinayreefer

Seems that trying to vacuum out the tank through the deck fitting would get stopped at the check valves on the diaphragm pump if it's working right, and since it's leaking, would suck in air. The previous owner confessed to never having done dockside holding tank cleanout.
Will pumpout work? I ask because the tank is nearly full and the pump is fritzed and I'd like to keep crap out of the boat!

Seems like a very strange arrangement to me but if you are being sprayed when you try to pump out are you sure the pump isn't simply installed back to front ?

pinayreefer · #9 (**permalink**) 07-28-2011

Quote:

Originally Posted by CaptainForce

I can't say that there is only one right answer, but simple usually trumps. I pump everything to the holding tank with no Y-valve........

'just a T fitting after the tank will allow pump out or a macerator pump to overboard depending on your location. I have no Y-valve, but the locker to my through-hull is locked and the handle has been removed while the through-hull is left in the closed position. This is in full compliance and remains simple. Take care and joy, Aythya crew

I posted this thread to get help to understand these systems and thanks so much but to help me understand better in your setup, "it would seem"

that your setup would depend on a check valve in the head to prevent backflow out of the tank into the head, unless the head was elevated above the tank. I don't think mine is or isn't much higher, anyway. After reading more and drawing out the check valves in the diaphragm pump, I think drawing a vacuum on the discharge end of the pump will open both checks and allow the liquid from the tank to pass through it. I'll try it tomorrow anyway at the pumpout station, then if it works I'll flush with water then remove the pump and try and figure out why it leaks.
Thanks everybody for contributing to my understanding of this system!

pinayreefer · #10 (**permalink**) 07-28-2011

Quote:

Originally Posted by tdw

Seems like a very strange arrangement to me but if you are being sprayed when you try to pump out are you sure the pump isn't simply installed back to front ?

I should have mentioned that on the delivery voyage home the first time I pumped out the tank it worked fine, but the second time is when I got sprayed, so I think it was installed right discharge/suction - wise.
Someone suggested that maybe I didn't have it valved correctly at the Y when I tried to pump it out the second time and that might have happened, or when I pumped it out the first time a chunk of solid material (aka "turd") might have lodged in the discharge check, stopping it up so the pump was dead-heading that way and blew the diaphragm loose. For sure trying to remove the pump when the lines and pump are full of foul smelling fluid isn't any fun so I'll try the pumpout first and hope it works or go to Plan B which involves buckets, gloves, mask, probably a wooden plug, some PVC couples and pipe to make a temp line to the deck fitting so it can be pumped out that way. Whew! Welcome to the world of old boats!