Newbie Help - Dredge with 4" trash pump

[Vitz]

Admittedly, I'm a newbie. I'm not interested in prospecting for gold but I'm interested in dredging muck and sand from around my dock. There seems to be more useful information on your website than anywhere else I've found. I've read and read and read but am still not sure what I should do so I'm hoping some of you will lend me some advice, especially since I won't be your competition!

I already own a 4" trash pump. I was originally just planning on using the intake hose and strainer to suck up the mud/sand and move it about 100 feet onshore. Then I started reading about venturi nozzles and that seems to be the better way to go so that the mud/sand doesn't run through the pump. I tried building a venturi from PVC based on what I'd read but it was big, unwieldy and ultimately blew apart. So I'm thinking about buying a pre-made jet nozzle. Biggest I can find is a 4" nozzle with a 2" inlet. Is that the way to go and, if so, how do I reduce my outlet hose from my pump from 4" to 2"? Any web links to recommended products would be appreciated.

I'll be happy to consider any other options or information you all provide.

 

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[russau]

You would be better off using a back hoe ! Using a suction device WILL LOWER the water level in the pond if it is shallow and not fed with more water. Plus if you used a suction device ,where will you dump the waste water? and when useing a suction device the entire pond will become a muddy mess for several days.

 

[Vitz]

It's actually a saltwater canal connected to a bay so I'm not worried about water level. We own the vacant lot next door and my plan was to pump the waste water there. I can't get a backhoe to the location.

 

[mikep691]

Relatively easy to reduce the output side. Get a 4" to 2" black iron reduction bell, and a 2" nipple. That's the cheap part. Now the expensive part: you'll need 100' of 4" rigid hose and enough 2" pressure hose to reach the nozzle from your pump with enough extra to move the nozzle around your dock. You should check with the local authorities about permitting too.

 

[Vitz]

So something like this?

Bell - https://www.plumbersstock.com/blkbr42-4in-x-2-black-bell-reducer.html

Nipple - https://www.plumbersstock.com/galn212-2in-x-12-galvanized-nipple.html

Why do I need 100' of 4" rigid hose? My plan was to put the pump on the dock so I can use the 20' of rigid intake hose I already have for the water supply from the canal. I was thinking I could just use 6-8' of 4" hose (does it need to be rigid?) to the reducer and then have enough 2" hose to use the nozzle around the dock and canal.

Sorry for the thousand questions. I'm just trying to get my head around how this would work. Thanks.

 

[mikep691]

So something like this?

Bell - https://www.plumbersstock.com/blkbr42-4in-x-2-black-bell-reducer.html

Nipple - https://www.plumbersstock.com/galn212-2in-x-12-galvanized-nipple.html

Why do I need 100' of 4" rigid hose? My plan was to put the pump on the dock so I can use the 20' of rigid intake hose I already have for the water supply from the canal. I was thinking I could just use 6-8' of 4" hose (does it need to be rigid?) to the reducer and then have enough 2" hose to use the nozzle around the dock and canal.

Sorry for the thousand questions. I'm just trying to get my head around how this would work. Thanks.

Yes on the reducing bell. The nipple can be close-close, very short.
You said you wanted to move the silt 100'. In order to do that you need 100' of 4" hose from the nozzle. It needs to be rigid to prevent clogs and hose collapses.

 

[mikep691]

Your 2" hose goes from pump output to the nozzle. This creates suction for the nozzle. 6-8' of 4" hose will only move the silt 6-8'.

 

[Vitz]

I follow you now. You're suggesting I put the reducer directly on the pump. Somewhere I read you should reduce it as close to the nozzle as possible rather than at the pump.

 

[mikep691]

I follow you now. You're suggesting I put the reducer directly on the pump. Somewhere I read you should reduce it as close to the nozzle as possible rather than at the pump.

Six in one hand, half dozen in the other. Think of it this way, one 2" hose is a lot easier to manage at the nozzle. And you already have a 4" hose output from that nozzle. Also reducing at the pump creates pressure and that pressure is what creates the suction.

 

[mikep691]

Is there a deep channel in the canal? You may only need to move the silt 20' or just enough to clear your dock. That will save you money and work.

 

[Vitz]

No. It's a very narrow, dead end canal and I'm at the dead end. Over the years, the silt/sand has built up at the end of the canal. I really just need to get some of the muck out and not rearrange it.

 

[mikep691]

No. It's a very narrow, dead end canal and I'm at the dead end. Over the years, the silt/sand has built up at the end of the canal. I really just need to get some of the muck out and not rearrange it.

Not sure where to go with that. Unless blowing the silt out of the canal onto dry land is an option. Like your first thought of using the pump intake to pull the silt through the pump, then all you need is lay flat hose from the output side. Just have to make sure there are no rocks to damage the impeller. Fine silt and sand should pass through the pump.That way you won't need a nozzle or rigid 4" hose. If your 4" input has a 1/4" screen, you should good to pass material through the pump. Just the desired length of 4" lay flay hose with the fitting type to go to the output on the pump.

EDIT: I just went back and see you want to move the silt 100 feet ONSHORE. All you need is the output hose for the 4" pump. As long as the strainer on the input is 1/4" or smaller, it's best to pass the silt through the pump. Lay flat hose is a lot cheaper and you won't need the nozzle or reduction bell.

 

[Vitz]

Well that would certainly be simpler and cheaper. I've already got all the lay flat hose I need. Last question (I think) - Is there a 1/4" strainer you can buy? If not, what's the best way to make one?

 

[mikep691]

Well that would certainly be simpler and cheaper. I've already got all the lay flat hose I need. Last question (I think) - Is there a 1/4" strainer you can buy? If not, what's the best way to make one?

https://www.firehosedirect.com/foot-valve-strainers Kind of pricey. I've used 1/4" hardware cloth in a pinch.

 

[mikep691]

If you have a Prospecting shop nearby, something like these work:

 

[N-Lionberger]

The 4" footvalve strainer from Keene is like 200 bucks. I bought one relatively recently. If you are running a trash pump I assume it is self priming if so it doesn't need a footvalve. Keene makes a 4" jet with a 3" eductor. Do not restrict the size of the pump outlet, run as large pressure hose as you can and make your restriction at the jet. On the discharge end for straight runs PVC pipe can be used instead of hose, it is sometimes cheaper to be had locally than long lengths of 4" semi rigid hose. 4" Power Jet with 3" Jet Log: Keene Engineering Online

 

[russau]

Why buy a foot valve when they are so EZ to make your own and it's not like he's going to be using it very much , probly once or twice !