Holding Tank Pumpout Mods.

[gengiant]

Hi,

Has anyone on this list done any modifications to their holding tank pump out plumbing that would allow one to pump out when the boat's on the trailer, say, at an RV dump station? I am thinking that there's got to be a way to "Y" into the hose downstream of the macerator pump. I could imagine a hose connected to this "Y" fitting with the other end connected to a thru-hull fitting on the side of the hull above the water line. If this fitting was threaded on the outside it should be pretty simple to connect/thread a stud to it on shore with a discharge hose connected to it, leading to a sewer cleanout such as an RV dump at my storage yard.

This all sounds almost too simple, so what am I overlooking? I've seen switchable "Y" valves at West Marine, so that'd be easy. What about the threaded thru-hull and connection? Does such a thing exist? Anyone know of a source? Alternatively, has anyone solved this issue another way that they wouldn't mind sharing? :smt024

Thanks all!

 

[Alex D]

Can't you jsut use the deck fitting to pump out?? :huh:

 

[MLauman]

Can't you jsut use the deck fitting to pump out?? :huh:

Think he wants to use his macerator as the pump. That won't pump out the deck fitting.

There was a long thread about this on the 'other board', and I don't recall any bright ideas being shared. I do remember the thread morphed into a discussion on using a wet/dry vac to pump out in the driveway. Yuck!

What you're describing is technically feasible. Don't know where you're gonna get that threaded connnector though - maybe an RV shop?

 

[gengiant]

I apologize, but there seems to be some confusion as to what I am hoping to do. Of course, using a std. marine pump out station is the preferred m.o. - no question. But around here, that's not allways possible. It allways amazes me how few public pumpout facilities there are around here, or if one is available, how much they charge to use it. That's why I was trying to figure out if there was an alternative that would allow me to clean out the waste once on land. And since the boat already has a pump, ie the macerator pump, plumbed to dump, it would seem that an alternative solution would take advantage of that. Sounds like I need to think about this one some more, 'cause the last thing I want to do is create a 'mess'.

 

[CharlieN]

We are using a similar idea on our 268 Sundancer as a pumpout substitute. I bought a ¾ pipe tap and threaded it into the macerator discharge thru-hull on the bottom of the boat. I then thread a ¾ inch pipe to 3/4 inch copper pipe fitting into the bottom of the boat. I use a hose clamp to connect a flexible 1†hose to the outside of the fitting, then run the hose into a 5 gallon bucket, or RV type portable waste container or if the hose is long enough, directly into the RV dump drain in the ground. The boat has to be on the trailer of course. Works well for us.
Charlie N
268 Sundancer
‘About Time’

 

[gengiant]

We are using a similar idea on our 268 Sundancer as a pumpout substitute. I bought a ¾ pipe tap and threaded it into the macerator discharge thru-hull on the bottom of the boat. I then thread a ¾ inch pipe to 3/4 inch copper pipe fitting into the bottom of the boat. I use a hose clamp to connect a flexible 1†hose to the outside of the fitting, then run the hose into a 5 gallon bucket, or RV type portable waste container or if the hose is long enough, directly into the RV dump drain in the ground. The boat has to be on the trailer of course. Works well for us.
Charlie N
268 Sundancer
‘About Time’

Hi Charlie,

I can't quite picture your installation :smt017 , but it sounds somewhat like what I had in mind. If I understand you correctly, your installation happens entirely on the outside of the boat, ie you did not re-plumb anything between the macerator pump and the blackwater throughhull? Was your throughhull threaded to begin with or is this something you had to do? Do you have any pictures of this you could share? :smt024

Thanks a bunch!

 

[CharlieN]

GG:
Thats correct-no mods to inside of the boat.
The thru-hole fitting looks like it was made for threading. It is very close to the correct size for 3/4 inch pipe threads.
I used the 3/4 inch pipe tap laying on my back underneath the boat turning ithe tap with a wrench. Very little metal is removed from the thru-hole. About 4 or 5 good threads are all that is required to get a good seal.
The boat is down in Mexico at the moment so no pictures are available. Sorry.
Charlie N
268 Dancer
'About Time'

 

[gengiant]

GG:
[...snip...]
The boat is down in Mexico at the moment so no pictures are available. Sorry.
Charlie N
268 Dancer
'About Time'

Lucky Dog! :thumbsup: Must be nice, boating down in Mexico, that is.

Anyway, from your last description I pretty much "get the picture". The next time I am "visiting" my boat (it's sitting in a storage yard) I will need to check the accessibility of the throughhull for the sewer discharge. I have a bunk trailer, so it may not be quite as accessible. If it is, however, I will pursue a solution like you described. I like the simplicity and cleanliness of it! :smt038

Thanks!