Using RV dump?

[John]

Hi Peggie,I trailer-sail and several of the lakes around here lack a pumpout station. I was thinking it might be convenient to stop at an RV dump station when driving home and use an external pump to empty the holding tank. Can you give me any advice about what kind of pump, hose, adapter (anything else?) I would need for this, or if it is just an all-around dumb idea?Thanks!

 

[Peggie Hall/Head Mistress]

Not a dumb idea...

Except the pump has to be INternal, not external. If the boat already has an overboard discharge thru-hull and seacock, it's fairly easy: break the pumpout line and put a y-valve in it...one side going to the deck pumpout fitting, the other side going through a pump (macerator or manual) to the thru-hull. You'll also need a hose that has a fitting on the end of it that you can jam into the thru-hull and hold it there while the tank is pumped "overboard" into the dump station. This makes dumping the tank a two-person operation...one person outside to hold the hose tight in the thru-hull, the other onboard to operate the pump. If there is no thru-hull, or you usually are alone, it can also be done by installing a "by-pass" in the pumpout line...y-valve at one end, tee or wye fitting at the other end...pump installed in the bypass. You'd still need the external hose, but you can fit it with a threaded fitting that threads into your deck pumpout fitting. Dangle the hose over the side into the dump station and turn on the pump.

 

[John]

"Macerator or manual" pump

Thanks, Peggie. You mentioned using a macerator or manual pump. Did you mean to exclude electric waste pumps that don't macerate? From what I gather, the advantage of these pumps is that you don't destroy them if you accidentally run them dry. I assume the drawback is a higher risk of clogging without maceration?Any advice about the type of pump or specific pumps would be great. Thanks again.

 

[Peggie Hall/Head Mistress]

Didn't intend to exclude diaphragm pumps

Manual pumps ARE diaphragm pumps...electric is good too. No more danger of clogging than there is when pumping out through the deck fitting. Solid waste and the right kind of toilet paper dissolve very quickly.

 

[John]

Macerator advantages?

Okay, if clogging is not really an issue, does a macerating pump have any advantages over an electric diaphragm pump?Thank you.

 

[Peggie Hall/Head Mistress]

Nothing except price

A macerator costs about $100 less than a diaphragm pump. However, it's not hard to make up that difference replacing impellers.A macerator does fit in a smaller space than a diaphragm pump...but that's offset by the ability to put a diaphragm further from the tank.