How to empty a big holding tank... boat in yard...

[Uncle Bob]

Originally Posted by Aquadome

I can't believe what I'm reading with the suggestions being offered. Call a mobile service and have them send their truck it's fast efficient and environmentally friendly. Who wants to mess with that mess ... how cheap are you?

+1

[a64pilot]

Originally Posted by Dymaxion

OK, if you insist on a DIY....

Get a 5gal water can, they have large mouth screw on cap with valve. The hole is same size as a shop vac hose, plugs in tightly. Find a plastic two part plastic tank fitting with size same as the pump out hose on your tank, or a bit smaller. Drill hole through top of water jug and fit the thru hull in.



Fit pump out hose onto fiting, using duct tape as needed. Plug shop vac into main water jug hole and turn on the vacuum. Watch the crap fill your 5 gal jug quickly, quit before the tank is full. Cap off and go dump it down nearest toilet. Repeat until holding tank is empty. This was bearable for a 12 gal holding tank, Hate to do much more....

If I understand what you are saying, just use 55 gl drum instead.
Of course then you have a drum that weighs about 500 lbs if full though.

[Calif.Ted]

7.48 gal./cu. ft. times 8 cu. ft. equals 59.8 gallons tank capacity, be sure to video if you decide to DIY.

[Rowglide]

Dug an old jabsco macerator pump out of my parts pile, made an $8.00 adapter and am pumping all the goodness into a 5 gallon jug works great. It'll take a few trips to dump it all in our septic at home but that is the only close disposal source.
Working well!
I'll take pictures.

[peghall]

Originally Posted by Rowglide

Dug an old jabsco macerator pump out of my parts pile, made an $8.00 adapter and am pumping all the goodness into a 5 gallon jug works great. It'll take a few trips to dump it all in our septic at home but that is the only close disposal source.
Working well! I'll take pictures.

Once you've pumped out all the waste, 'twould be a good idea to rinse out the tank...you don't want to leave sludge in the bottom to harden into concrete. Put a few gallons of water into the tank via the pumpout fitting--'cuz that sends the water into the tank at the bottom to stir up any sludge--and suck that out. Repeat a few times.

[jamhass]

Glad you have a working solution.

FWIW. Before I finally installed a macerator pump, I could only empty my holding tank from the deck outlet. I found a nice, inexpensive whale diaphragm pump that took 1 1/2 inch hose and could draw to 5 feet. Screwed it to a bit of plywood for stability, and that with a few nylon plumbing bits worked just fine for 6 years. Still does work, but I finally installed a macerator.

[markpierce]

Hire a local, mobile pump-out service or go to sea and empty the tank yourself by opening a valve. I use the first option.