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Specifications and Features Of The 8 Inch Dredge “Norma Lee”


1) Designed And Built By Dredging Specialists In 1979.  Has completed over 150 projects in 22 states.

2) Rebuilt In 2007: New main pontoons, new side pontoons, new ladder, new ladder mounting, new A frame, new hoist winch, all four hydraulic pumps were rebuilt, new swing winch proportional speed control valve with electronic potentiometer speed control, new bearings in swing winches, rear winch and forward winch, new bearings and seals in hydraulic pump drive gear box, gears were like new.  All new hydraulic hoses.  New hydraulic pipes and tubing on the ladder.  Completely rewired the dredge. New flow meter for dredge pump discharge.  New hydraulic valve and new micro switches for digging head flip-flop.  Replaced one digging head hydraulic cylinder.

3) Stretched To Dig 26 Feet Deep: In 2007, thirteen foot long extension pontoons were built and bolted on the front of the main and side pontoons to provide the flotation needed to extend the digging depth from 17 feet to 26 feet.  The new ladder has 3 sections.  The front and rear sections are bolted together to dig 17 feet deep.  To dig 26 feet deep, a center section is bolted between the front and rear sections.

4) Construction. A fabricated backbone made from 3/4 inch and 1/2 inch plate, is 8 feet wide, 2 feet high and 1.5 feet front to rear, and provides a strong structure to mount:

a) The ladder trunnions.

b) The main pontoons, which are welded to the front of the backbone.

c) The bilge which, is made from 3/16” thick plate and is welded to the rear of the backbone.

The engine and hydraulic system are mounted in the bilge.
The pontoons are built from 11 gauge plate with baffles every 5 feet, which provide separate water tight compartments.  The internal reinforcing structure is made from 2” by 2” and 4” by 4” square tubing.

5) Length: In the long configuration, the dredge is 49 feet long.  In the short configuration, the dredge is 36 feet long. 

6) Draft and Freeboard:  Pontoons are 27 inches deep, which provides 9 inches of freeboard and 18 inches of draft.

7) Side Pontoons Fold Up: The side pontoons are hinged to the main pontoons and fold up and make the dredge 8 feet wide for trucking and fold down to make the dredge 13-1/2 feet wide in the water.  A crane that is needed to set the dredge from the trailer into the water is used to fold the side pontoons down. 

8) The Weight Of The Dredge is 33,000 pounds in the short configuration and 38,000 pounds in the long configuration.  In the short configuration, the dredge can be hauled on a step deck trailer and is legal in all respects.  In the long configuration, the dredge is hauled on a double step deck trailer that has a sliding extendable frame.  In the long configuration, an over length permit is required.  

9) Fuel Capacity: Two 155 gallon tanks, one in each main pontoon.  Total capacity 310 gallons, will run the dredge 6 to 7 days.

10) Engine: Deutz F8L-413-V8, air cooled diesel engine, rated 220 horsepower.  
Advantages of Air Cooled Diesel Engines: Forty percent of all problems with liquid cooled diesel engines are caused by the cooling system.  Radiators leak, water pumps fail, hoses fail, overheat from loss of coolant, heads crack, antifreeze gets in the oil, must check and change the antifreeze,  With Deutz air cooled diesels, you have none of these problems.  Without a radiator sticking out in front of the engine, air cooled engines require less space.
The engine rebuilt in 2002 and has 2,274 hours since rebuilt.  Summery of rebuild:
New Parts: Cylinders, pistons, piston rings, wrist pins, wrist pin bushings, rod bearings, main bearings, camshaft, camshaft bushings, valve lifters, exhaust valve guides, exhaust valves, oil pump, bushings on fuel injector pump drive, all seals and gaskets.
Parts that were checked and found to be in serviceable condition: Intake valves, intake valve guides, valve springs, valve seats, ball bearings on the fuel injector and blower drives, rocker arms, rocker arm pivot pins, push rods, injectors.
 Reconditioned Parts: Grind valve seats, grind intake valves, grind rocker arms where they pivot on the valves.
Engine Automatic Shut Down Protection: The engine will stop if it overheats for any reason.  The engine will stop if more than five gallons of hydraulic oil is lost from the hydraulic reservoir.  This limits pollution and saves hydraulic oil.

11) Underwater Dredge Pump:  Designed and built by Dredging Specialists.  Has a 21 inch, three vane impeller, with twisted vanes.  12 inch inlet and 8 inch outlet.  RPM 1100.  
Flow rate, 2,200 gallons per minute, at 120 feet of head.  Has a mechanical face type seal and a service water pump that provides clean water that flushes the seal for extended life.  Will pass a
6 inch spherical solid.  Has a 3 inch diameter shaft with Timken tapered bearings.  We have never broken the pump shaft.  Has two 5 feet long walkways that fold down, one on each side of the dredge pump.  The walkways permit servicing the digging head and dredge pump without getting in a boat. 
On a recent project for the City of Philadelphia, PA, we dredged 300,000 cubic yards of river mud.  We averaged 204 cubic yards per pumping hour on a 1,500 foot pipeline.  We averaged 29.3% insitu solids.  
Why an Underwater Dredge Pump?  Decomposing organic material causes gas to form in most industrial and municipal sludge as well as river and lake mud.  When an above water dredge pump is used, the high vacuum needed to move the material up the suction pipe will cause the gas bubbles to expand, fill the pump with air and the pump will stop pumping.  This is called cavitation. When an underwater pump is used, there is no suction pipe and the head of fluid above the pump provides .4 pounds of supercharge pressure per foot of submergence.  Thus, less vacuum is needed to get the material into the pump.  Thus, the gas bubbles do not expand as much and there is much less cavitation.  With an underwater pump, you do not have to prime it as you do with an above water pump.

12) Digging Head:  Dredging Specialists Design 8 head.  Click here to see a picture.
Provides a cut that is 3 feet wide by 1.5 feet high.  Cutting force is greater than a loader bucket on a Case backhoe loader tractor.  Two hydraulic cylinders flip-flop the head for left or right cuts.  The ladder has a four bar linkage which keeps the cutting edge of the digging head, flat on the bottom, regardless of the depth at which the dredge is digging.

13) Sampler Valve: Hydraulically opened and closed from the cab.  Permits the operator to see what he is pumping and recover samples.

14) Dredging Specialists Exclusive 4 Cable Positioning And  Swing System: It is common knowledge in the marine industry, that to hold a vessel in a fixed position, at least three anchors are required.  An analogue is a chair.  To be stable, a chair must have at least three legs.  Four legs work well and are commonly used.  A chair with two legs is unstable and only a fool would make a chair with two legs.  However, the folks that make auger dredges, only use two anchor points on the dredge.  This is like a chair with two legs.  An auger dredge is easily pushed out of the cut by the wind, and also when there is material on one side and water on the other side of the dredge.  When these forces push an auger dredge out of the cut, it pumps water and there is no means on the dredge to get it back in the cut.  The only solution is to move the dredge where there will be material on both sides of the cut at all depths.  This leaves a ridge of material between each cut. 

The dredge, Norma Lee, uses a four cable system which is like a chair with four legs.  Click here to see a drawing of the four cable system.  The dredge is accurately positioned to keep the dredge pump suction in the material.  The dredge is accurately and continuously moved by the swing winches, explained below, which maintain the pump suction in material.  The Norma Lee is the only dredge of its size, which will swing a continuous arc of 350 feet.  This means less water is pumped because there are fewer stops and changes in direction.  This means greater production.  With the winches on the dredge, the Norma Lee can be placed anywhere in a rectangle 350 feet by 130 feet.  It can be easily and quickly backed up to make cleanup cuts.  It can be quickly moved to shore for fuel or repairs.
When you come to our shop to see the dredge, I will demonstrate our four cable system and you will clearly see the advantages it has over an auger dredge or a 3 cable system.

15) Hydraulic System And Winches:  All the functions of the dredge are hydraulic powered.  Three hydraulic pumps are mounted on a Funk three pad gear box that is mounted on the engine flywheel housing.  The reservoir holds 110 gallons of oil and is 3/4 submerged for cooling.

a) Dredge Pump Drive: Closed loop hydrostatic transmission using a Denison P6P Cold Cup axial piston pump and a Rexroth 15 cubic inch per revolution bent axis piston motor. 

b) Hoist Winch.  Bloom 1400 series, hydraulic powered, worm drive, with a spring applied hydraulic released brake.  Denison vane pump.  Maximum line pull 15,000 pounds.  Will hoist the ladder from 26 feet in less than 30 seconds.  Has Dredging Specialists exclusive Bird Nest Eliminator which prevents tangled cable.  Click here to see an example of a Bird Nest Eliminator.

c) Swing Winches: Has one for left swing and one for right swing.  Designed and built by Dredging Specialists.  Cessna, load sensing axial piston pump with Parker low speed high torque motors.  Eskridge spring applied hydraulic released brakes on each winch.  Drum holds 350 feet of 3/8 cable.  Swing speed variable from 0 to 150 feet per minute.  Maximum line pull 3800 pounds.  Both winches have Dredging Specialists exclusive Bird Nest Eliminator, which prevents tangled cable.
To swing left, move the left swing lever to the detent position, it will lock in.  The left swing winch will wind in and the cable on the right swing winch will be pulled off with an adjustable tension.  The swing speed is adjusted with a potentiometer.  

d) Forward Winch Called The Lock Winch:  Bloom hydraulic powered worm drive.  Holds 130 feet of 3/8 cable.  Line speed up to 100 feet per minute.  Line pull up to 8,000 pounds.  Has a dog clutch that permits free spooling. 
In the cut being made, this winch is locked and  the cable cannot wind in or out.  The swing winches cause the dredge to swing on the arc made by the distance from the dredge to the forward anchor on the shore.  When the cut is completed, this winch is used to move the dredge forward for the next cut, or back for cleanup.  Has Dredging Specialists exclusive encoder that permits the operator to see the distance he is moving forward.  Click here to see a picture of the encoder.

e) Rear Winch Called The Rubber Band Winch: Built by Dredging Specialists.  Has a Char-Lynn low speed high torque motor, with hydraulic released spring applied brake.  A dog clutch provides free spooling. 
This winch is always trying to wind in with an adjustable tension.  When the load on the cable is greater than the setting, the winch winds out.  When the tension on the cable is less than the tension setting, the cable winds in.  This permits the cable length, from the dredge to the shore anchor, to change as the dredge swings.  It provides a constant tension on the rear cable and also the forward cable.  With constant tension on the forward and rear cables, as well as tension on both swing cables, as explained in item 15-c, the cabling system holds the dredge pump suction pipe in material, at all times, as the dredge swings. 

16) Hydraulic System Filtration:  Three micron, full flow filters, with a Beta ratio greater then 200, provides filtration to ISO 18-15-11. This provides double the life of hydraulic components compared to other dredges.  New oil is not clean enough to be used in a hydraulic system.  When adding oil, it is common for sand and other debris to fall from the lip of a five gallon can into the reservoir.  To clean new oil and eliminate sand and other debris from entering the reservoir, all oil entering the reservoir is pumped in through a 3 micron filter.  The hydraulic reservoir has a Greer clean vent.  The clean vent does not permit outside air to enter the reservoir as it breathes, from the oil heating and cooling.  This prevents condensation in the reservoir, which leads to water in the oil, which substantially shortens the life of the oil and the hydraulic components.  The combination of fine filtration, filtering all makeup oil and the clean vent will more than triple the life of the oil and the hydraulic components, compared to other dredges.  Long oil and long hydraulic component life will lower your repair expense, increase your production and income by many thousands of dollars.

17) Fuel Efficiency: With the price of diesel fuel today, fuel efficiency is a most important consideration.  By using a high efficiency piston pump and a piston motor for the dredge pump drive, along with a load sensing piston pump for the swing winches, fuel efficiency is better than dredges that use open center gear pumps. 
On a 300,000 yard project, pumping 1500 feet, production was 27 cubic yards per gallon of diesel fuel.  At a cost of $4.00 per gallon, the cost per yard for fuel was $0.15.

18) Booster Pump and Barge:  The pump was designed and built by Dredging Specialists.  10 inch inlet and 10 inch outlet.  2000 gpm at 110 feet of head.  Powered by a Deutz BF6L 913 six cylinder air cooled diesel engine rated 150 horsepower.  Skid mounted for ease of placement on the shore or on the barge.  

a) Engine Overhauled in 2003. Hours since overhaul 1,545.  Overhaul summery:
New Parts:  One new cylinder and piston, rings, rod bearings, main bearings, exhaust valve guides.  All other parts within specifications.  Ground valves and seats, honed cylinders, rebuilt belt tightener, and rebuilt the injectors.  Installed Donaldson 6 micron filter.

b) Rebuilt the Pump: June of 2008, 0 hours since rebuilt.  Installed new wear plates in the suction inlet.  Hard faced the case as needed.  Rebuilt and balanced the impeller.  Installed a new seal.

c) Booster Pump Barge:  Main barge is 16 feet long, 8 feet wide and 2 feet high.  Made from 11 gauge plate with internal reinforcement and baffles to support the booster pump.  Has three water tight compartments.  The center compartment is a 500 gallon fuel tank.  Side pontoons are 16 feet long, 2 feet wide and 2 feet high.  Made from 11 gauge plate with internal reinforcement and a baffle that makes two watertight compartments.  Side pontoons bolt to the main barge and are removed for trucking.  Draft is 10 inches with 14 inches of freeboard.
The booster pump barge is attached to the dredge using pintle hooks, [Pintle hooks are used to pull a trailer] and two steel tubing linkage bars.  This provides flexibility between the dredge and the booster barge.  A walkway permits walking from the dredge to the booster barge.

19) Handrail:  Has Dredging Specialists exclusive user friendly handrail on the dredge and booster pump barge.  Provides entry to the dredge or booster barge at any location at any time.  Click here to see a picture of the handrail.  Once you use it, you will love it.

20) Equipment To Make A Complete Dredging Plant.

a) 10 Inch Pipe: 4,800 feet of 10 inch aluminum pipe in 30 feet lengths..  Rated 200 psi.  Floats that will make 525 feet of floating pipeline.  A 4’ length of rubber hose goes between each 30 foot floating pipe and provides a flexible floating pipeline. Gaskets and quick coupling clamps, couple the pipe together.  Fourteen 90, 60, and 30 degree elbows. 

b) 12 inch pipe: 1,525 feet of 12 inch aluminum pipe in 30 foot lengths.  Rated 150 psi.  Floats to make 600 feet of floating pipeline.  A 6’ length of rubber hose goes between each 30 foot floating pipe and provides a flexible floating pipeline.  Victaulic clamps and gaskets are used to couple the pipes together and make a leak free pipeline.  Two 90 degree steel elbows, one steel tee, one 90 degree aluminum elbow. 
The Reasons We Use Aluminum Pipe:  Lightweight, two men can easily carry a 30 foot pipe. Easily and quickly laid out and coupled together using common tools.  Easily banded together for loading and shipping.  2,200 feet per truck load.
We have used aluminum pipe for over 30 years.  We have 10 inch pipe that is over 30 years old and still in service.  We have 12 inch pipe that has pumped 850,000 cubic yards of river mud that contained 42,000 yards of sand, and 8,500 yards of gravel and rocks, up to 6 inches and the wear was .013”.  

c) Cable: Comes with 5,000 feet of new 3/8 inch cable.  Comes with two Dredging Specialists exclusive cable stands.  These stands can be placed on sloping ground and the shaft, nor the cable spool, will not slide to the side and dump the spool on the ground.  Stands will hold spools of up to 4,000 feet of 3/8 cable.  4 spool stands with crank handles for cable or rope.  Click here to see cable stands.
Comes with 500 feet of 1/2 inch Poly rope and 1, 200 feet of 3/8 Poly rope.
Comes with four Dredging Specialists exclusive cable clamps.  These clamps permit you to dredge a pond or lake, of any length, without cutting or splicing the front or rear cables that go from the the dredge to shore anchors.  

d) Cable Floats: Comes with six Dredging Specialists exclusive cable floats.  These floats are made from two 55 gallon drums with a steel frame that holds the cables 5 feet above the water.  They are placed 300 to 500 feet apart on the front or rear cables.  They hold these cables above the water and prevent them from sinking to the bottom and dragging in the mud, which would inhibit the dredge when swinging.  They are bolted together, come apart, and are placed in a wooden rack for ease of shipping.  Click here to see a picture of the floats.

e) Barges:  Fuel barge: One 18’X 6’X 2.5’ hopper barge with a 500 gallon fuel tank in the hopper.  The hopper provides spill containment.
One, landing barge: 6.5’ X 9.5’X 2’ Used to tie up work boats at shore.  Comes with a 35 feet long by 3 feet wide bridge that provides a walkway from the landing barge to the shore.   Is ideal when the water level varies due to tides or rain.  The bridge is bolted together and comes apart for ease of shipping.  Click here to see the landing barge and bridge.
One utility deck barge.  14’ X 6 X 2’.
One 300 gallon fuel tank with steel spill containment, used on shore.

f) Tool Boxes & Shipping Boxes:  Two, Knaack steel job boxes, 5’ X 2’ X 2’.  One, 3’ X 2’ X 2’ steel tool box with slide tray that is on the dredge.  One, Craftsman 12 drawer mechanics tool box, with mechanics tools.  Mounts on a stand on the dredge. 
Three, steel frame, plywood covered, open top shipping boxes, 8’ X 4’ X 4’.  Used to ship pipeline clamps, gaskets, elbows and other items.

g) Anchors: Nine, shore anchor plates with 25 car axels, which are driven with a sledge hammer through holes in the anchor plates.  Two, heavy anchors for use in the water.

h) Pinch Valves: Three, hand operated pinch valves for 10 inch hose.  One, hydraulically operated pinch valve for 10 inch hose.  Pinch valves are used to pinch hose together to stop backflow which causes turbidity, and stop backflow to clean out the booster pump.

i) Work Boats:  One, 15 feet long flat bottom Jon –boat with 9.8 HP Nissan electric start outboard motor.  One, 14 feet long flat bottom Jon-boat with 6 HP Mariner outboard motor.

j) Rigging Items:

i)   Assortment of Open Wedge Sockets. [often called Beckets or wedge blocks]  Used to attach a cable to an anchor plate.  Used to attach two cables together.

ii)  Assortment of screw pin shackles.

iii)  Assortment of cable clamps.

iv)  Two cable grabbers.

v)   Assortment of chains with grab hooks on each end.

k) Spare Parts:

i)   Dredge pump cartridge.  Consists of the impeller, shaft, shaft housing, bearings, and seal.  The cartridge is assembled and can be changed in 2 hours.  Seal life approximately 500 hours.

ii)   Two dredge pump seal assemblies. 

iii)   Spare motors for swing winches, forward and rear winches.

iv)   Filters for dredge, booster pump, and hydraulic system.

v)   Solenoids for hydraulic valves.

vi)   Seals for booster pump.

vii)  Other items too numerous to list.

l) Tools and Equipment.

i)   Electric tensioning tool for Bandit banding. 

ii)   Hand operated tensioning tools for ½”, Ύ” and 1” Bandit banding.

iii)   Assortment of ½” and Ύ” banding and clips. 

iv)   Tools to press steel fitting on the ends of aluminum pipe.

v)   Tools to press steel fittings in 12” hose.

vi)   Tools to rebuild the dredge pump and booster pump.

vii)  Other tools too numerous to list.

To inspect the dredge call Don Searles at 217-259-2229