What a way to wake up. 150m dredger right beside us.

[thesaltytar]

Time to drop pipes and beat them with two handed sledge hammers?

That's what we had to do when offloading concrete or barite from pneumatic tanks. Pressurize the tank, open the valve, and all that powdered stuff flies out of the pipes.... Until someone goofs up and closes a valve too much (it has to have the right amount of back pressure or the whole thing fails) and the pipes pack solid.

[emoji849]

[RaymondR]

There's a very interesting operation being carried out in Western Australia for a cement manufacturing plant.

The feed stock for the plant is calcareous sand which is dredged from the seabed in Cockburn Sound and loaded into clamshell barges for marine transport to a jetty where it is dumped onto the seabed by the entire two sides of the barge hinging open. A suction dredging arm on the end of the jetty then picks the sand up and delivers it to large screen separators where it is washed with fresh water and larger pieces, shells and any junk are taken out. It is then pumped by two massive positive displacement, high pressure, plunger pumps through a 7" pipeline seven kilometers to the cement factory.

[GILow]

Originally Posted by RaymondR

There's a very interesting operation being carried out in Western Australia for a cement manufacturing plant.

The feed stock for the plant is calcareous sand which is dredged from the seabed in Cockburn Sound and loaded into clamshell barges for marine transport to a jetty where it is dumped onto the seabed by the entire two sides of the barge hinging open. A suction dredging arm on the end of the jetty then picks the sand up and delivers it to large screen separators where it is washed with fresh water and larger pieces, shells and any junk are taken out. It is then pumped by two massive positive displacement, high pressure, plunger pumps through a 7" pipeline seven kilometers to the cement factory.

Larger pieces of shells, junk and cruisers' anchor chains are washed out...

[El Pinguino]

Originally Posted by GILow

Larger pieces of shells, junk and cruisers ' anchor chains are washed out...

Fixed it for you.

[4runner]

Originally Posted by Franziska

Hi,

I am not sure where to post this, but it may spin into a safety discussion, hence I put it here.

We are currently at anchor in a designated anchor area in Leixoes Port (Oporto, Portugal).
A Dutch company is dredging the harbour with a number of vessels, amongst them some of the biggest of their kind in the world.
The anchor area is not cordoned off and noone came to ask any of the yachts to move.

This morning the 150m long hopper suction dredger woke us up, working not even 50m. 2x 1.20m suction pipes make for an infernalic sound :-)
We did not feel threatened, because we saw the green giants moving about very gently yesterday, but, the sheer size and sound give you some pause.

Do we have anyone here who has been professionally involved in dredging who can explain how they avoid sucking up chain, anchor or anything unwanted and the procedures they would follow if they did?
Attachment 263503Attachment 263504

Just move!!

They’ve got a job to get done for the good of the port and the ships that use it.

Don’t make their work any more difficult just because you’re anchored in a designated anchorage. The designated anchorage likely needs to be dredged to accommodate deeper draft ships- no concern there for recreational vessels.

You’re concerned about your anchor, and you know that the situation could be resolved by just moving. Why stay?

Basic seamanship…..

[Franziska]

Originally Posted by 4runner

Just move!!

They’ve got a job to get done for the good of the port and the ships that use it.

Don’t make their work any more difficult just because you’re anchored in a designated anchorage. The designated anchorage likely needs to be dredged to accommodate deeper draft ships- no concern there for recreational vessels.

You’re concerned about your anchor, and you know that the situation could be resolved by just moving. Why stay?

Basic seamanship…..

This was a designated anchorage for yachts within the harbour.

No one requested us to move at any time. and there was no need to move. We did not impede them.

They do not dredge this corner of the harbour, but a diagonal line 50m parallel to it where they dredge down to 18m.
They were moving very professional.

My question was purely hypothetical as to what would happen if they swallowed a yacht anchor.

[smacksman]

When they dredge a marina on the R. Orwell and pump the silt ashore, it is like a beachcomers paradise to walk over the spoil. Winch handles; knives; etc. The dredgers told me they can suck/blow a car tyre down an 8" pipe for 400 yards.

[JC Reefer]

Originally Posted by smacksman

The dredgers told me they can suck/blow a car tyre down an 8" pipe for 400 yards.

Interesting. I may have met such a dredger. She liked dirty martinis. 🤭

[AKA-None]

Originally Posted by Franziska

This was a designated anchorage for yachts within the harbour.

No one requested us to move at any time. and there was no need to move. We did not impede them.

They do not dredge this corner of the harbour, but a diagonal line 50m parallel to it where they dredge down to 18m.
They were moving very professional.

My question was purely hypothetical as to what would happen if they swallowed a yacht anchor.

They would likely suck it in and pull you to them until someone noticed and shut down the pump

Then they would commence looking for damages to determine how to unwind the terminal gear and if they needed to dissect the system to remove it

The only one I worked on had pretty much no or little filter on the intake

[donradcliffe]

Originally Posted by JC Reefer

Interesting. I may have met such a dredger. She liked dirty martinis. 🤭

Like the Willie Nelson line--I gonna find one of them Keno girls that can suck the chrome off a trailer hitch.

[Franziska]

Originally Posted by AKA-None

They would likely suck it in and pull you to them until someone noticed and shut down the pump

Then they would commence looking for damages to determine how to unwind the terminal gear and if they needed to dissect the system to remove it

The only one I worked on had pretty much no or little filter on the intake

Thank you. Good explanation.