Dredge Holland Still Digging
Lucas Marine Construction is using the 1914 California dredge Holland on emergency dredging in the Sacramento Delta. Unusually high rainfall – 180 percent of normal — has saturated the ground and created seepage under the dikes, a precursor to dike failure. Lucas and other Northern California dredging contractors are fortifying the dikes by reinforcing the dikes with permeable rock material.
Last November, the company completed a levee-bolstering project that consisted of placing more than 100,000 cubic yards of dredged material on the back sides of the levees of Tyler Island, in the Sacramento San Joaquin Delta near Rio Vista, California.
Aside from being converted from steam to diesel power in the 1950’s, the dredge Holland remains unchanged since 1914. Then-owners Olympian Dredging Company, replaced the steam engines with two Detroit Diesel 610 engines of 350 hp each, and one 225hp Detroit Diesel 671, which operates the swing and also moves the spuds.
With its 172-foot boom, the Holland can dig and deposit material more than 300 feet from the digging point. Using an eight cubic yard Stockton bucket, with a cycle time of less than one minute, the dredge can achieve 40 to 45 swings per hour, with moves, moving about 1500 cubic yards per 10-hour shift.
The Stockton bucket was the evolution of bucket designs for digging large amounts of mud, developed to hold as much mud as possible and light enough to be handled by the long boom cranes. Because of the round design, material can stack up better, without voids, said John Lucas, vice president of Lucas Marine Construction, Inc. The final design was the best possible in light of the materials and fabrication methods of the day.
Lucas uses two Stockton buckets, 5 ½ cubic yard (seven yards heaped) and 6 ¼ cubic yard (eight yards heaped.) Though the buckets are no longer manufactured, Lucas Marine’s fabrication shop keeps them in good repair, said John Lucas. They are made of mild steel, with a hardened steel lip, and one bucket is equipped with teeth.
The bucket closes like ice tongs, by lifting on the arms. The longer the arms, the harder material it is possible to dig, said Lucas. Opening is by cables attached to the edges of the shells.
Operators must have a high degree of skill. Besides digging, the bucket is used to move the dredge forward. Two of the three spuds are raised and the bucket placed ahead. Drawing on the lines swings the dredge forward. This process is repeated until the dredge is in position. Because the levees in the Sacramento delta are very delicate, material must be carefully placed by lowering the bucket to within a foot of the levee before opening it.
Sally Lucas is president of the company, which she purchased, along with her husband John, in 1988. At that time it was little more than a pile driving company, but they added dredging equipment over the years. In their early 30’s, the Lucas’s employ a highly skilled crew in their fabrication shop and on their dredges, and are a significant presence in the Northern California dredging industry.
Other equipment is a 12-inch hydraulic dredge named The Producer and a derrick barge Little Joe, which uses a six cubic yard, heavy digging bucket.
Their activities are not confined to dredging. They have built two 120- by 50-foot barges in their fabrication shop, and are building a third one. They are repairing the stern of a Greek freighter, and have built several tugboats.
“California” type dredge
3 – 34-inch x 70’ square spuds
Hull: 120’ x 60’ x 10’
Gantry height: 60’
Boom length: 172’
Line pull: 60,000 lbs., 700hp, 1 ½” cable
Line speed: 240 fpm
Capacity: 8 cy heaped
Swing: 180 degrees, 310 reach, 225hp
Cycle time: less than one minute
All steel construction