Suction "Dredge"

[Chris-B]

Ok my turn for a question now to those who know far more than me about these things !

 

We are investigating the possibility of making/purchasing a cost effective "dredge" unit

This has come about due to our new mooring getting the entrance silted up by the nearby barge running his engine in gear

and blowing all the silt into the entrance of the inlet we are moored in

 

2 1/2 hours on Friday night to get out of the arm Pi55ed me off somewhat !!!!!!

 

Has anyone got experience of such a thing ? what we need to do is suck the silt/water from the inlet and pump it into a holding tank for the water to drain off

the silt can then be used in other areas

 

Bit like the kit wreck recovers use but cheaper !!!

 

Chris

[barge sara]

Would something like this do it?

 

http://www.dredgebrokers.com/Dredges_Hyd/9...-DH/Dredge.html

[dove]

Would something like this do it?

 

http://www.dredgebrokers.com/Dredges_Hyd/9...-DH/Dredge.html

 

or something a bit smaller http://www.selwoodgroup.co.uk/pumps_pump-rental.html

 

Andrew

[Chris-B]

love to play with that BUT we need something more hand manageable

 

hose which we can move to clear the high spots with really

 

Industrial vacuum cleaner on steroids

 

C

 

 

Edited to add

 

That's more of what we need Andrew

Now to try and get one at the right price !

 

C

Edited October 26, 2009 by Baldock

[Keeping Up]

If you get one, we might know of somewhere else that it could be useful

[barge sara]

In a previous life I did some marine Civil Engineering work.

We used to employ a diving firm to clear silt and they used home made suction dredgers,

Fundamentally a 3 inch or thereabouts pipe about five feet long with a couple of handles welded on and an inlet for compressed air half way up, which inside the pipe bent up to face the outlet end. Injected compressed air induced a flow in the pipe which was very good at shifting silt.

These of course operated completely submerged and simply threw the silt up to be carried away by the tide. Not sure how you would adapt to suit shallow water and the outlet being in the open air. Need some way of 'priming' the pipe and controlling the resulting shower of s**t!

 

HTH.

[Athy]

Perhaps asking the barge owner to run his engine in reverse gear might help?

[RLWP]

In a previous life I did some marine Civil Engineering work.

We used to employ a diving firm to clear silt and they used home made suction dredgers,

Fundamentally a 3 inch or thereabouts pipe about five feet long with a couple of handles welded on and an inlet for compressed air half way up, which inside the pipe bent up to face the outlet end. Injected compressed air induced a flow in the pipe which was very good at shifting silt.

These of course operated completely submerged and simply threw the silt up to be carried away by the tide. Not sure how you would adapt to suit shallow water and the outlet being in the open air. Need some way of 'priming' the pipe and controlling the resulting shower of s**t!

 

HTH.

 

Perhaps you should put the outlet in a large container of water. Something like the hold or hull of a barge?

 

Richard

 

I'm sure you could find one conveniently local?

[howardang]

Ok my turn for a question now to those who know far more than me about these things !

 

We are investigating the possibility of making/purchasing a cost effective "dredge" unit

This has come about due to our new mooring getting the entrance silted up by the nearby barge running his engine in gear

and blowing all the silt into the entrance of the inlet we are moored in

 

2 1/2 hours on Friday night to get out of the arm Pi55ed me off somewhat !!!!!!

 

Has anyone got experience of such a thing ? what we need to do is suck the silt/water from the inlet and pump it into a holding tank for the water to drain off

the silt can then be used in other areas

 

Bit like the kit wreck recovers use but cheaper !!!

 

Chris

We used to use airlifts in marine salvage operations and they are also used for marine archeology; see this link for an idea of how they work and can be constructed.

 

http://www.weymouthdiving.co.uk/equipment.htm

 

Be careful of running foul of the EA with regard to dredge spoils. Dredging operations are subject to licence, fees and quite rigid controls.

 

Howard

[Chris-B]

We used to use airlifts in marine salvage operations and they are also used for marine archeology; see this link for an idea of how they work and can be constructed.

 

http://www.weymouthdiving.co.uk/equipment.htm

 

Be careful of running foul of the EA with regard to dredge spoils. Dredging operations are subject to licence, fees and quite rigid controls.

 

Howard

 

I am not dredging it , just moving it back to the owner !!!!!

[Strads]

Chris..

 

erh - stout bucket on a strong peice of rope and try scrapping the the channel..?

 

saw a 2inch dia water pump at the week end - petrol driven for @ 190 squid (from memory)

 

would think it could suck of silt thats been stirred up into the water - case of then placing the out streat some where where the silt isnt an issue.

 

give me a bell to discuss if needed

cheers

[mayalld]

I am not dredging it , just moving it back to the owner !!!!!

 

Yeah, that though occurs to me.

 

Due to the fact that BW haven't dredged our bit of the canal since... Well given that they haven't actually dredged it ever, and that it has gone undredged since the 1970s when volunteers re-opened the canal, it is getting steadily worse.

 

Passing boats keep the main channel open, by ploughing a furrow, which pushes 35 years of silt to the sides, and silts up our mooring. BW will then endearingly claim that they aren't responsible for dredging our moorings.

 

I can find no rules that prohibit us using a trash pump to redistribute silt from our mooring into suspension in the channel, where they will settle out a bit further downstream. Perhaps they will dredge it when boats can't get through.

[mykaskin]

We are investigating the possibility of making/purchasing a cost effective "dredge" unit

This has come about due to our new mooring getting the entrance silted up by the nearby barge running his engine in gear

and blowing all the silt into the entrance of the inlet we are moored in

 

Just use your boat to push it back again - if you want I can bring Victoria down there (once I fix my engine) and do a bit of thrashing to shift that silt!

 

You could do what Associated British Ports (ABP) do, and use a big drag towed behind a tug which just pulls the mud into a deeper channel!

 

Mike

[Chris-B]

Just use your boat to push it back again (That's exactly what we did Fri and Sunday to get out/in)- if you want I can bring Victoria down there (once I fix my engine) and do a bit of thrashing to shift that silt! lol cheers for the offer Mike but the Baldock plough does the job

You could do what Associated British Ports (ABP) do, and use a big drag towed behind a tug which just pulls the mud into a deeper channel! Mmmmm now theres a thought :lol: :lol:

 

 

Just use your boat to push it back again (That's exactly what we did Fri and Sunday to get out/in)- if you want I can bring Victoria down there (once I fix my engine) and do a bit of thrashing to shift that silt! lol cheers for the offer Mike but the Baldock plough does the job

You could do what Associated British Ports (ABP) do, and use a big drag towed behind a tug which just pulls the mud into a deeper channel! Mmmmm now theres a thought ;)

[mykaskin]

Victoria is 1/2 foot deeper than a town class, so it may still clearer for longer... BTW where have you moved to? (if you don't mind me asking!)

 

Mike

 

ps. May be getting her loaded this winter, so could be even deeper!!!

Edited October 26, 2009 by mykaskin

[Tim Lewis]

Ok my turn for a question now to those who know far more than me about these things !

 

We are investigating the possibility of making/purchasing a cost effective "dredge" unit

This has come about due to our new mooring getting the entrance silted up by the nearby barge running his engine in gear

and blowing all the silt into the entrance of the inlet we are moored in

 

2 1/2 hours on Friday night to get out of the arm Pi55ed me off somewhat !!!!!!

 

Has anyone got experience of such a thing ? what we need to do is suck the silt/water from the inlet and pump it into a holding tank for the water to drain off

the silt can then be used in other areas

 

Bit like the kit wreck recovers use but cheaper !!!

 

Chris

 

http://www.siltbuster.com/FB50-OWS.html

 

Tim

[Heffalump]

 

 

:lol:

[Phil Ambrose]

In a previous life I did some marine Civil Engineering work.

We used to employ a diving firm to clear silt and they used home made suction dredgers,

Fundamentally a 3 inch or thereabouts pipe about five feet long with a couple of handles welded on and an inlet for compressed air half way up, which inside the pipe bent up to face the outlet end. Injected compressed air induced a flow in the pipe which was very good at shifting silt.

These of course operated completely submerged and simply threw the silt up to be carried away by the tide. Not sure how you would adapt to suit shallow water and the outlet being in the open air. Need some way of 'priming' the pipe and controlling the resulting shower of s**t!

 

HTH.

 

Been racking my brains to try and recall how a bit of kit functioned. It was about 45 years ago so a bit , no very hazy, when I was an apprentice one job I worked on was making swimming pool vaccume cleaners. All I can recall was a wide poss 18" nozzle which had a width of about 1" fixed to a long 2" dia pipe and this was connected to a hose pipe.

I suppose in essence a hydraulic "air" lift

Edited October 26, 2009 by Phil Ambrose

[Ermenilda]

In a previous life I did some marine Civil Engineering work.

We used to employ a diving firm to clear silt and they used home made suction dredgers,

Fundamentally a 3 inch or thereabouts pipe about five feet long with a couple of handles welded on and an inlet for compressed air half way up, which inside the pipe bent up to face the outlet end. Injected compressed air induced a flow in the pipe which was very good at shifting silt.

These of course operated completely submerged and simply threw the silt up to be carried away by the tide. Not sure how you would adapt to suit shallow water and the outlet being in the open air. Need some way of 'priming' the pipe and controlling the resulting shower of s**t!

 

HTH.

 

Used a similar thing in past commercial diving days - steel pipe suspended from a crane on a barge with a compressor pumping air into the pipe about a foot or two from the 'mouth' of the pipe - worked a treat! slightly more manageable was years ealier constructed a home made device for a bit of 'treasure hunting' which was an old flexible plastic pipe with a hole stabbed in it couple of feet up the pipe and a feed from a seperate diving cylinder stuffed into the hole - both had the outlet totally submerged to work though but were probably a good 20ft+ long

 

However - it's something I thought about in the past for silted up moorings and I can't see why you couldn't still do something like this - compressor on the boat (cheap if you have one already or can beg/borrow/steal ) with feed pipe stuck in couple of feet from the end of a long flexible pipe - cable tie a barge pole to the pipe to keep the 'hoover' bit rigid and 'managable' from the boat - put a bouy on the exhaust end and point it in the direction you want the silt to end up - turn on the compressor and point the barge pole at the area you want to hoover up! I think it would work although the relatively shallow depths involved/boyles law for air expansion from depth/resulting suction power etc. may not come into play here and it 's not going to get the silt out of the water but I think it would allow you to move it somewhere else more convenient? dunno if that is 'legal' tho? no idea...

 

Wouldn't cost much and sure it would be loads of fun!

[Guest User]

Not sure how big a job you've got but if the main aim is to "re-distribute" the silt back to its original owner, would something like a long-hosed pressure washer do the job ? That is, if you did something like strap the lance to a boat pole to hold it under with ? .... might have problems operating the trigger remotely though.

[RLWP]

Surely you've got a 50 gallon oil drum and an angle grinder about:

 

 

 

Richard

[nb Innisfree]

In my past life when I was in the fire service we used to have a 'Hughes Noble ejector pump' this was basically a tubular tee piece aligned as in a T with a connector on one side

of the T to fit a hose and allow water to be pumped through to the opposite side of the T to which a length of outlet hose was connected. The bottom of the T was connected to a length of large diam. hard suction pipe. Due to a venturi effect across the T a massive suction is applied to the hard suction which is capable of removing large quantities of water and mud through the water outlet without blocking up. We used it for emptying cellars or raising sunken boats etc. Very effective

 

Hope I have explained clearly.

Edited October 26, 2009 by nb Innisfree

[Chris-B]

Many thanks everybody, plenty to go on with.

 

Off to have a think and chat

 

Chris

[ditchcrawler]

In my past life when I was in the fire service we used to have a 'Hughes Noble ejector pump' this was basically a tubular tee piece aligned as in a T with a connector on one side

of the T to fit a hose and allow water to be pumped through to the opposite side of the T to which a length of outlet hose was connected. The bottom of the T was connected to a length of large diam. hard suction pipe. Due to a venturi effect across the T a massive suction is applied to the hard suction which is capable of removing large quantities of water and mud through the water outlet without blocking up. We used it for emptying cellars or raising sunken boats etc. Very effective

 

Hope I have explained clearly.

We used something very similar to move air through large tanks and vessels for maintenance, it this case we used compressed air to suck large volumes of stale air from the tanks allowing fresh air in through the man-way.

http://www.nexflowair.com/pdf/air_amplifier.pdf

 

pdf added

Edited October 27, 2009 by ditchcrawler

[johnjo]

Turn his boat round!