Holding tank discharge pump

[ian w]

I do most of my boating on my 53 my in the Bahamas where we like to use the holding tank in the marinas.
Pump out facilities are few and far between.i would like to be able to pump out at sea .How and where is the best way to install the pump?
Ian w

[MikeP]

I mounted a macerator pump on the top surface of the forward holding tank and then made up a valve that would allow me to select either holding tank to pump from. Some additional hose/valves will probably be necessary, depending on how your system is currently set up.

To operate the overboard pump-out requires that I open the forward cabin floor hatch/kneel down to access the switch/valves. It's not super convenient but it works fine and since I hardly ever actually use it, it's not problem. You could set up the whole thing in one of the engine rooms for easier access if you used it on a regular basis. it's just a matter of running the hose to wherever...

[krush]

You can tee a pump into the suckout pickup. Put an isolation valve before the newly installed pump. That's how mine was down by a previous owner....used a diaphragm pump. Vacuflush pretty much obliterates everything so no macerator needed. Diaphragm pump doesn't need to be primed. Put a key switch on it to make the poop patrol happy.

[Bob Bradley]

On my 43C, the hose that goes from the holding tank up to the gunwale pumpout fitting runs behind the closet wall in my v-berth. I cut that hose, and installed a y-valve in it. One side of the y continues to feed the deck fitting, and the other runs to a macerator, which then pumps out a hose that attaches to a bronze thru-hull fitting just below the waterline. The handle of the y-valve is accessible in the closet, and I keep it secured in the deck pumpout position with a wire tie.

[Toolsntoys]

Mine is set up like bobs. The only thing I added is a key switch that activates the mascerator pump. Coast guard regulations requires the system to have a lock out feature. I'm not sure if the lock out has to be on the valve tho. I do believe that most of the head setups that discharge before the holding tank are no longer legal and require a locking type valve I don't think a wire tie is considered a lock. Please correct me is im wrong it make for good discussion

[Pascal]

The easiest way is to put a Y valve in the hose going to the pump out as close to the tank and as accessible as possible For pumps the vacu flush is the best. Stay away from the cheapo impeller macerateds, they always burn out

A key switch is a legal way to comply with the regs, as long as the key is not left on the switch or a zip tie on the valve or pulling the sea cock handle

You should also have a vented loop in the discharge line between the pump and the thru hull if below waterline even though in theory the duckbills in the VF pump should prevent syphoning

[Toolsntoys]

Pascal. If the loop goes up over the waterline does it still require a vented loop. I don't think my boat has a vented loop but it does have a loop.

[Pascal]

In theory it shouldn't syphon back thru the Duckbills of a SEalnd pump but it could. I ve always seen a vented loop on factory installs

[Bob Bradley]

On my setup, the y-valve really obviates the need for the vented loop, as long as I keep it in the deck pumpout position (which it always is, unless I am actually pumping it out).

[Dan Mapes]

We used a macerator and we are glad we did. Once in a while a piece of calcium gets into it and you can hear it buzz into pieces. If a good chunk of calcium gets in a vflush pump the only way to resolve it is to disassemble it all and then take about 5 showers.

The easiest was as said earlier. A Y valve into the pump out line that directs the effluent to the pump out or macerator/thruhull.

The people in marinas thank you for holding it.