waste pumpout

[trickyrick]

The marina that I'm at has a portable sewage tank on wheels with a manual pump like the one in the link
https://www.amazon.ca/Whale-Marine-...ocphy=9000994&hvtargid=pla-571845011678&psc=1
There is a small hose coming out of the tank at the top looks like it's just used for a vent.
Id like some info on how the hand pumps work. My intent is to use a vacuum compressor of sorts say from an old fridge and connect it to the vent hose to create a vacuum in the portable holding tank but I'm not sure how the manual pump is made not sure if the waste would flow freely through the valve without pumping it
Any thoughts

 

[Peggie Hall HeadMistress]

I see you just joined our merry band today...welcome aboard

There is a small hose coming out of the tank at the top looks like it's just used for a vent.

Not sure from your description whether the vent in question is on your holding tank or the portable pumpout tank, but wherever it is, it should not be blocked. Tank vents have two very important functions...they provide an escape for air displaced for incoming contents and a source of air to replace contents as they're drawn out. So you need both vents--the one on your holding tank to provide the source of air to replace contents...without it the pump or whatever pulls waste out of it would pull a vacuum in the holding tank that would let anything be pulled out, and without an escape route for the air being displaced in the portable pumpout, that tank would pressurize, resulting in consequences when the pumpout is disconnected from your tank that you definitely won't like. So I strongly suggest you use it as it's designed to be used.

You'll find user instructions for one of the Whale waste pumps here...https://www.manualslib.com/download/1339500/Whale-Gulper-220.html It may not be the same model as the one on the portable pumpout, but most manual diaphragm pumps work pretty much the same way, so you shouldn't have too much trouble figuring out how to use that one. It's actually pretty simple, really.
--Peggie

 

[trickyrick]

Thanks for the input
There is one vent on the portable tank (not on the boat) the boat tank is vented all the time. I can understand the need for the vent on the portable tank so as when the sewage is pumped in the air can be displaced. I want to take that vent hose and connect it to a vacuum pump so as to create a low pressure in the portable tank that in turn will suck the waste into the portable tank. when the portable tank is near full I can stop the vacuum pump and slowly let air back into the portable tank. Then I would remove the vacuum pump from the vent letting me to remove the contents from the 1 1/2 tap at the bottom of the tank. I hope this clarifiys what I would like to do. I just was not sure how the manual pump was made but you seem to think that the sewage will flow freely through the pump

 

[shemandr]

You should check with your Harbormaster as to whether or not there is a pump out boat service. It is WAY more easy. Often it's free but decent people tip the operator. We had a social relationship with several of the operators and got very good service. It's all about not being a jerk to them. They can respond with "Poop You."

 

[twalker H260]

Check how hoses are attached to existing pump. I suspect it will be hose from boat, pump, hose to portable tank. This layout places vacuum in hose from boat and positive pressure in hose to portable tank. I would be worried about the portable tank collapsing, even under low vacuum. They are usually designed to accept waste at low positive pressure rather than vacuum. (Assuming this is some sort of plastic tank.)

 

[dlochner]

The Whale pump you posted from Amazon is a diaphragm pump. These pumps are pretty robust and will suck any soft substance up and through the pump. The pump is likely self-priming and can continue to pump stuff through the hose even after the tank is empty.

A diaphragm pump will allow stuff to flow through it if there is enough pressure differential. That is what you are proposing, reducing the pressure in the pump out tank so the stuff gets sucked in. It might work, but I have to wonder why the designers and engineers of the portable tank didn't go in that direction.

 

[trickyrick]

Thanks for all your input. I had not thought about the tank imploding from the vacuum. The diaphragm pump that the marina uses is not the exact model of the link I used I just used that so you would know what I was talking about. The portable tank the marina uses is about 20 gallons and it takes about 45 min to get to about 3/4 full. That's a lot of pumping when I have an 80-gallon tank. I was trying to devise something that would be a lot easier to use. As to using the service of the marina to pump out, I have no engine in my boat it's being removed. I live on the boat year round so I have to use the portable pump out

 

[fstbttms]

I want to take that vent hose and connect it to a vacuum pump so as to create a low pressure in the portable tank that in turn will suck the waste into the portable tank.

Oh brother. What could possibly go wrong?

 

[Benny17441]

Operating the pump requires extensive training, "move the handle up and down". The wheel has already been invented, messing with pressurizing the black water holding tank can have dire consequences.

 

[Peggie Hall HeadMistress]

Operating the pump requires extensive training, "move the handle up and down". The wheel has already been invented, messing with pressurizing the black water holding tank can have dire consequences.

I'd bet real money that Rick is an engineer... 'cuz normal people believe that if it ain't broke, don't fix it....engineers are convinced that if it ain't broke, it either doesn't have enough features yet or they have to keep reinventing it till it does break.

--Peggie
(I DO hope Rick has a sense of humor, 'cuz he only joined sbo.com yesterday and it's a bit soon to start treating him like family!)

 

[dlochner]

Whale makes an electric diaphragm pump that is designed for pumping out holding tanks.
https://www.defender.com/product.js...et-pump&path=-1|51|2234226|2234236&id=1285029

With some fittings and hose it would be possible to rig this to pump from the pump out fitting on your boat into the portable tank.

 

[dlochner]

Just stumbled upon this from Edson. 1 gallon discharge per stroke.

https://www.defender.com/pdf/500830_Edson.pdf

 

[Jim26m]

Dave beat me to it. Motorized pump is the way to go.
Interesting idea, though. Putting enough vacuum on a tank to pull the waste in will likely collapse the tank, unless it's a substantial tank. You might want to look at the displacement of the refrigerator compressor you're thinking of using also. It might take quite awhile to empty your black tank with that small vacuum source (haven't checked).

If you want it emptied quick, there are plenty of pumps designed for it. https://www.pumpahead.com/PDF/PAH40.pdf

 

[Peggie Hall HeadMistress]

PumpaHead makes installed and portable dockside pumpout equipment, which his marina already has, complete with tank (not shown in your link) to collect the waste. The only issue here is how to get it out of the tank on the boat into the tank on the dockside equipment. He doesn't seem to like the idea of using the manual pump on the portable dockside unit, and installing a macerator pump in the pumpout line on the boat to push it out the deck pumpout is definitely NOT the way to go. So I don't think there's any option other than using the manual pump on the portable unit.
--Peggie
(I just hope he's still here to read all that!)

 

[Jim26m]

Peggy,
Unless I'm mistaken, the pump I referenced is a motorized version of what is mounted on his current tank. I probably wasn't clear, but I was suggesting he motorize the pumping operation with a similar, but motorized pump. Pumpahead makes a few cart packages with motorized pumps - which would be my preferred solution (if there were no budgetary constraints).

I feel his pain, though. I wouldn't want to spend any more time at that task than was absolutely necessary!

BTW: Really enjoy reading your posts!
Jim

 

[JamesG161]

Just stumbled upon this from Edson. 1 gallon discharge per stroke.

Now that pump was a good find!

Now the key to all this is...

Who owns the pump and suction hose?

Remember someone has to clean and stow it.
_________
Roughly speaking, it takes the same amount of "human input" energy to manually pump 80 gallons of waste.

80 ... one gallon strokes
or
160 ... 1/2 gallon strokes.

I would think that there is not even much "time" improvement.
_______
My suggestion is to find a teenager and pay them $30 to do it all.
Jim...

 

[twalker H260]

If it’s taking 3/4hr to pump 20 gallons I’m thinking there may be an air leak on the suction side or the pump needs a rebuild. Most of the diaphragm pumps look to do 11gpm and up depending on length of suction hose so should really only take 2-3 minutes to transfer 20gallons (pumping slowly). Perhaps dealing with the leak/pump rebuild might be a better solution?

I built my own solution using a diaphragm pump and Rv tank on wheels. The air leak invariably was where the hose connected to the pump out fitting on deck. Teflon tape on a screw in fitting with clamp on hose couplings help.

 

[Peggie Hall HeadMistress]

Unless I'm mistaken, the pump I referenced is a motorized version of what is mounted on his current tank. I probably wasn't clear, but I was suggesting he motorize the pumping operation with a similar, but motorized pump. Pumpahead makes a few cart packages with motorized pumps - which would be my preferred solution (if there were no budgetary constraints).

What you're missing is, he doesn't own the portable pumpout cart, the marina does...and it's the pump on the cart that has to pull the waste out of the tank on his boat. I don't think they'd appreciate his replacing THEIR manual Whale pump with an electric pump, and besides, their cart may not even be wired for one. But even if it is, without a battery on the cart, what's gonna supply the power for it?
--Peggie

 

[Jim26m]

Seems like the thread started with hooking an electric vacuum pump to the cart, and being that he stated he lived aboard; I made the assumption that shore power was available.

He could put a new transfer pump in line and pump through the existing diaphragm pump if they wouldn't agree to letting him motorize the cart.

If he's got any game at all, a motorized pumpout cart would be a doable project, even if he had to start from scratch. If I had 80 gallons of black water to move fairly often, I would be motivated to find the fastest and cleanest way to do it.

I may have over-assumed. One of my many character flaws.

 

[trickyrick]

Thanks for all the good info. I think the best solution is what Jim26m suggests. Place a pump next to my onboard tank and pump the waste through the manual pump on the cart. Im thinking of getting this pump.
Peggie for power on the cart I would have just ran an extension cord
https://whalepumps.com/marine/produ...D=10027&FriendlyID=Electric-Black-Waste-pumps