Hydraulic Dredge by Steve Harvath

[Steve Harvath]

I am building a model of a hydraulic dredge that was used to dig part of the Chicago Sanitary Canal (the rather infamous project to reverse the flow of the Chicago River and send that city's sewage down to St. Louis).  I don't know if this qualifies as a nautical vessel.  It was basically a barge with a steam operated auger-suction device and a huge pump. In a curious way it was self-propelled.  It had a leg at the stern that allowed it to pivot and move forward as the work advanced.  I found a rather detailed plan and elevation of the dredge along with a small image of the 'as built' dredge in Engineering News, Sept 6, 1894.

[John Cheevers]

I like it! Have a good build.

[kurtvd19]

It floats - it's a nautical vessel.  An important one too.  I wonder just where it was used as most of the canal is cut through solid stone.  Looking at the drawing I think the vertical pole at the stern was a "spud" that could be lowered to hold the dredge in place and as you said it could pivot on the spud.  However spuds could only go up and down.  The piece of equipment that angles down off the stern (from what I can see of the photo) is probably part of the discharge tube for the material picked up by the dredge machinery and pumped to the stern and then deposited ashore or into hopper barges.  Sometimes dredges had discharge tubes that reached several hundred feet.

 

I will follow your build with great interest.   I am very interested in the canal and its history and have been on many tugs, towboats and barges on it.  I have done many models of tugs and towboats that operate on the canal.

 

I have 7 tons of stone from the building of the canal in my fireplace.  There were still piles of flagstone free for the taking n Lemont all the way to Lockport when my Father and uncle built this house in the early 50's.  Also have retaining landscaping walls of the flagstone.

 

Kurt

[John Cheevers]

I have long been interested in the ladder dredge Corozal which used to work the Canal zone in Panama. No plans, so I may have to reconstruct her from photographs.

[Steve Harvath]

Kurt,

 

Good to hear from you.  I looked closely at the drawing.  It is a small reproduction here I know.  It looks like that is a beam that angles off to the canal floor behind the stern. It has an iron spike at the end.  The beam is attached at the upper end to what looks like a piston.  So I think you are right that the single spud acts as a pivot when they put a little steam in that piston.  The discharge pipe is represented by an elbow above this contraption.  The contractors who had this dredge had contracts for about two miles of the canal. I am not sure where they were working.

 

John,

 

That is quite a machine.  Have fun.  I read that the techniques that were learned on the Chicago canal played a big part in the work on the Panama canal.

 

Steve

[Steve Harvath]

I have drawn a sketch plan so I have the waterline dimensions in 1:48.   The deck-to-waterline distance is only 18".  So at 1:48 I decided to use some clear pine 3/8" boards for the hull.  I glued and clamped two boards edge to edge and have marked out the deck plan.  The dredge had openings in the deck for the huge pump and for the boilers.  I am going to model these pieces of equipment.  The image of the dredge shows there are large openings in the sides of the deck house so the interior details that will be visible.

[Jim Lad]

Steve, dredgers are really interesting vessels.  I'll be following along on your build.

 

John

[Steve Harvath]

I have drawn the outlines of the dredge on the edge-glued boards.  I didn't have a curve template that was anywhere big enough to draw the curves. I used the top of an oval wastebasket. and that seemed to give me reasonable simulations of the bow and stern of the dredge.  The curved bow and stern must have had a function.  I think that they allowed the dredge to sweep back and forth to a greater degree within the channel it was digging.  A squared-off bow and stern would have limited the sweep.

[wefalck]

I have been collecting plans for dredgers for many years. I was particularly interestedin the chain-bucket dredgers, as there would be lots of visible mechanical parts to make on the lathe and mill.

 

The subject dredger is rather curious in the sense that the suction/cutting head could only move up and down. Normally, there would be a sort of ball-joint that would allow the head to swing in arc. Here the whole barge is pivotted on the ‚leg‘ in the rear and swung around. I suppose it would be moored off the business end and pulled to the left and right and forward too. However, I don’t see the usual winches.

 

will keep an eye on the progress.

[Canute]

Wefalck,  have you seen the Alaskan gold dredges? I attended a model railroad convention, back in June and this was one of the structure entries.

 

[wefalck]

As a geologist and environmental scientist, I am well aware of them. There is a sort of reality TV series on Discovery Channel on artisanal mining operations with such dredges. It makes me shudder, when I see the environmental havvoc they are causing ... 🤯

[reklein]

Wefalck, you should see some of the mountain valleys in Idaho where the dredges did there work. More than a hundred years ago now ,but one sees the huge piles of round boulders left by them.

 

[wefalck]

This is off-topic, of course: I spent the last 25+ years helping governments and intergovernment organisations to sort out such mining legacies and to prevent them in the future ...

 

Back to the shipping lane dredges (which can be also environmentally problematic ...)

[reklein]

Here in Idaho, Lewiston is technically a seaport even though we are 400 miles inland. Right now at harvest time the grain barges have lost their access to the coast because of cracks found in the locks structure downstream. Also a few years back we got to watch as encircle ments were made and dredge spoils were pumped in to make more land which was ultimately turned into an R/V park. Also clam shell cranes mounted on barges were used to deepen the barge landings. The spoils were loaded into more barges and hauled somewhere unknown to me. All interesting to watch. Meantime the steelhead fish and salmon population is way down

n.

[Steve Harvath]

Wefalck,

 

Yes This dredge must have pivoted on the single spud on the starboard side stern.  There seems to be a timber off the centerline of the stern that could be used to push the dredge around the axis of the spud maybe even push it forward to the next line of attack.

 

That is a nice model dredge -- bucket dredges are complicated.  I wonder if it had a prototype.  Here is the update for my dredge.  I have done a rough cut of the hull form using a plane and a keyhole saw.  I will plank the sides and build false decks in the wells in the deck that contain the pump and the boilers.

 

I grew up around the harbor in Santa Barbara, California.  They have a suction dredge there kind of like this one that has to constantly work to keep the harbor open. 

[Steve Harvath]

I have cleaned up the hull form with a rasp, chisel and sandpaper.  Now I will simulate the deck planks.  I was thinking of using a wood burning tool to burn the edges of the deck planks into the pine.

[kurtvd19]

I wouldn't try to wood burn plank seams - unless you are a true artist with the tool. Plank the hull with individual planks.

Kurt

 

[Steve Harvath]

Ah.  Well let me know how it looks.  I can always plank over the deck.  It will mellow out after I stain it.

 

[Steve Harvath]

I went on to plank the sides and the machinery wells at the bow and stern.  There is only 18 inches of freeboard so not many planks show.  I have started to add the rubrail as shown on the plans.

[Jim Lad]

Looking good, Steve.

 

John

[Steve Harvath]

I have installed false bottoms in the holds where the boilers and the pump will be placed.  I painted them flat black to improve the illusion that they are at full depth.  I made a mock-up of the deck house to see where the openings fit.  The plans do not show the doors or windows other than the windows at the bow.  There is one image of the dredge as-built that shows big openings in to the location of the pump and into the bay in front of the boilers, two tall narrow openings or maybe vents at the side of the boilers and a small window toward the stern.

[Steve Harvath]

I have framed the sides of the deck house.  I have been looking on the internet for images of the steam engine and pump.  I found one image of a smaller set up.  It looks like this kind of direct connected arrangement was most commonly used to power electrical generators. The drawing of the dredge seems to show a two cylinder, simple, high speed steam engine. The crank shaft of this engine is directly connected to the pump.

[Jim Lad]

She's coming along nicely, Steve.

 

John

[Steve Harvath]

I have finished putting the siding on the deck house and have started to develop the roof line of the deckhouse.  I don't have a cross section to work from.  I wanted it to appear that it could shed rain.  So I decided to give the roof a low slope -- something like 1:12 -- from a longitudinal ridge line.  There is a curious little framed outline at the stern.  I don't know what it was.  Maybe it was a head or outhouse.

 

A enterprising photographer caught one of the four boilers in transit to the shipyard.  The boilers are more representational than detailed models.  They are going to be mostly hidden in the smoky, steamy boiler room.

[Jim Lad]

She's really starting to look like she has a purpose now, Steve.

 

John

[Steve Harvath]

I have stained the deck and interior of the deck house.  This is so I can start to install the machinery and other details.  I stained the deck with a brown shoe polish and alcohol stain and the interior of the deck house walls with a black shoe polish and alcohol stain.  I think they would not have bothered to paint the interior walls so they just got smoky and had dirt and machine oil thrown on them.  I have test fitted the paired boilers in the deck house and the window frames.  I have made the spud which is a huge 17 inch by 17 inch timber that will extend 27 feet above the deck.   I am building the framework for the mechanism that lifted the spud.

[Steve Harvath]

Here is the spud lift mechanism and the spud painted and in place.   The spud was lifted by what I assume was a wire rope over the large diameter pulley.  There was a steam powered winch under the deck.  I plan on painting the hull black and the deck house a mineral red.

 

The harbor is getting pretty crowded.

 

 

[Roger Pellett]

Steve,  Nice work on an unusual subject.  Does this eventually become part of the railroad layout that appears in the background?

 

Roger

[Steve Harvath]

Yes.  I am building modules in 1:48 scale.  This will be a part of a harbor scene where I can highlight nautical models as well as maritime railroad operations.

 

 

[Steve Harvath]

I have begun to model the pumping machinery in the dredge.  I discovered a set of drawings of the steam engine that I am sure was used to power the centrifigul pump.  Westinghouse made high speed steam engines at the turn of the 19th century.  They were mostly used to drive generators which is probably why Westinghouse got into the steam engine business.  The engine is a two cylinder engine with an enclosed crankcase.  The cylinders were simple.  Located between the cylinders is a valve cylinder that is canted off at an angle from the vertical steam cylinders.  This shows clearly on the plan of the dredge.  The pump is very big -- around 9 feet in diameter.