Great Lakes' Biggest Dual-Mode ITB Begins Service

One of the most labor- and fuel-efficient bulk material carriers on the Great Lakes entered service in June 2000. The self-unloading barge Great Lakes Trader is owned by Great Lakes Marine Leasing, Portland, Ore., and operated by VanEnkevort Tug and Barge, Bark River, Mich. The 740 x 78 ft. (226 x 24 m) Trader is the largest vessel capable of fitting through the St. Lawrence Seaway locks. Combined with the 10,200-bhp (7,600 bkW) tug Joyce L. VanEnkevort, the new integrated tug/barge (ITB) unit is the biggest dual-mode ITB on the Great Lakes.

The 39,600 long ton (40,234 metric ton) capacity Trader was designed by a team of engineers directed by naval architect Joe Fischer, president of Bay Engineering, Inc., Sturgeon Bay, Wisc. Halter Marine built the vessel in two halves at their Pearlington, Miss., facility and finished it at their Gulf Repair Yard in New Orleans, La.

The self-unloading design incorporates internal gravity-fed gates leading to a hydraulically driven single-belt Ems-Tec conveyor system capable of unloading 6,000 long tons (6,096 metric tons) of iron ore pellets, coal, or crushed limestone per hour.

This efficient ship unloading system receives power from seven Cat 3406C engines rated 462 bhp (345 bkW) at 1,800 rpm. The 3406s drive Rexroth and Vickers multiple pump hydraulic drive units. This arrangement, with multiple engines rather than one or two larger engines, allows greater flexibility in the barge's operation. Engine service is easier to coordinate, and the crew operates only as many engines as are needed.

Barge electrical power is provided by a Cat 3406C gen set rated 260 ekW at 1,800 rpm. Cat Dealer Ohio Engine Power, Cleveland, Ohio, provided all pump engines for Great Lakes Trader, and Cat Dealer FABCO Engine Systems, Green Bay, Wisc., provided the generator set.