Page 18: of Marine News Magazine (August 2005)

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slurry per hour at 10,000 ft. via a booster pump arrangement.

At the end of the 5,000 ft. of pipe, a small barge holding a skid mounted pump is driven by a diesel engine. This arrange- ment will boost delivery of the slurry an additional 5,000 ft.. The pump, similar to the one located on the dredge, is direct driven by a Caterpillar 3516 diesel engine.

The engine is rated at 1,855 hp at 1,200 rpm.

The engine has a 1,950-gallon diesel fuel tank located within the main skid frame. The engine is turbocharged, after cooled and uses a radiator to cool the cir- culating water. Operation of the booster pump is controlled from the control house of the dredge via a radio wave intercon- nection between the dredge and the boost- er pump station.

A Lufkin gearbox reduces the booster engine rpm from 1200 to 490 rpm.

One of the unique features of the Goetz is the production monitor that takes a sampling every second of cross-sectional density and the flow rate within the slurry pipe giving a momentary mass flow. From that value the volume of solids in cubic yards or tons per hour can be calculated.

The Goetz has three capstans, two for- ward and one aft. Three 10 hp electric motors controls the operation of the cap- stans.

A davit-style deck crane is located for- ward and is sized to handle main deck components and be able to place the largest single pump component on the barge along side of the dredge.

The vessel has two spuds, both in the aft end of the vessel dredge. One is a "walk- ing spud" that allows precise movement of the vessel during dredging operations.

The other spud is for position holding while resetting the walking spud. Electric motors lift and lower both spuds via winches. The zero position of both spuds is when they are at the bottom of the hull.

Each spud is 42 ft. long, 30-in. in diam- eter with a 1.25 in. average wall thickness.

The spuds are encased in spuds wells.

The Goetz is equipped with cutter heads attached to a ladder that lowers to the river bottom. A 150 HP winch is provided and utilizes the OEM 3000 series drive system for control of both speed and torque. Two additional 150 hp Lantec winches are supplied as swing winches for lateral movement of the ladder with its cutting head.

The cutter head has a 352 hp electric motor derated to 302 hp. The electric motor also has a speed reducer to bring the rpm down to 50 rpm for the cutter head.

Power for this diesel electric dredge comes from a pair of Caterpillar 3516 B diesel engines connected to generators producing 1,285 kW each. The engines are four-cycle, ABS certified, Marpol compliant, turbocharged and after cooled.

The generators are capable of being run in parallel. A box cooler is used to cool the engine water.

Fuel for these two engines comes from a pair of 12,500 gallon tanks in the hull of the Goetz.

OEM chose generator engines running at 1,200 rpm M rather than 1800 rpm for several reasons including a 12 percent reduction in fuel consumption over a

Caterpillar 3412 engine running at 1800 rpm.

In addition, the 1200 rpm engine reduced exhaust emissions, noise, mainte- nance and increase engine overhaul time.

OEM also supplied the switchgear and generator control panel. A shore power connection is also supplied with a shore power breaker and a phase sequence- reversing switch is included to correct the incoming phase of the current.

Much of the electrical control equip- ment is centralized within an electrical control room on the main deck. The space also con- tains transformers to supply 120 volts and lower voltage for other equipment.

The second deck is dominated by the control house 14 ft. x 14 ft. x 10 ft. It is air conditioned and heated with 360 degree tinted glass windows, an operators con- sole, an operator's chair and anti-vibration mounting.

The control house sits atop a day room to give the control house operator a better line of sight to spud equipment and to view the surrounding river conditions.

The dredge Goetz has replaced the 67- year-old dredge William A. Thompson. "The Thompson was the last of its breed, a self-propelled hydraulic cutter dredge with quarters on board," said Jim May- bach, plant engineer. "The Thompson was one of the last vessels built with a wrought iron hull. You can't buy wrought iron anymore," Maybach added.

The Goetz is unpowered and offers no crew quarters or galley. It will take a fleet of four boats to replace the Thompson.

SeaArk Marine, Monticello, Ark., has delivered the crew boat Peck in June 2005 and the towboat General Warren will be completed in 2006. If funded, the quarters barge Taggatz will be completed in 2007.

The dredge cost $9.8 million, the tow- boat $5.6 million and the quarters barge $10 million and the crew boat $2.6 mil- lion.

That brings the total fleet cost to $28 million. It is expected to increase the pro- duction by 30 percent plus reduce fuel costs and cut potential pollution from hydraulic oil spills and diesel engine exhaust emissions significantly.

The dredge William A. Thompson is expected to stay with the new dredge sup- plying quarters and a galley until those functions are available from the new ves- sels under construction.

The dredge Goetz will be used to main- tain 850 miles of the Upper Mississippi

River, 355 miles of the Illinois River and 24 miles of the St. Croix River to a depth of nine-ft. in the channel. 18 • MarineNews • August, 2005

DREDGE REPORT

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