Eastern Shipbuilding Group, Panama City, Fla., has been selected to build a trailing suction hopper dredge ATB for Great Lakes Dredge & Dock Co., Oak Brook, Ill. 

The dual-mode ATB unit will consist of a 433'×92'×36' dredge barge and a 158'4"×52'×32'9" tug. Ship’s Architect Inc., Daphne, Ala., will handle the detailed design for the ATB dredge barge, GLDD151, and Bay Engineering Inc., the engineering arm of GLDD, will handle the same responsibilities for the tug, GLDD302. Both designs are based on an Ocean Tug & Barge Engineering ATB design.

Great Lakes had entered into an estimated $94 million contract with Signal International back in 2012 to build what was billed as the first ATB trailing suction hopper dredge. The original delivery date was the second quarter of this year. The agreement eventually fell apart, and Great Lakes went looking for another yard to build the ATB. Enter Eastern.

During the fourth quarter, GLDD inked a deal with Eastern for the construction of the ATB dredge, Jonathan Berger, GLDD CEO, said in a statement. 

“The vessel construction contract is approximately $140 million inclusive of equipment and materials we have already purchased and will provide to the shipyard for installation,” he said.

The ATB is expected to be delivered during the second half of 2016. “We continue to be very excited about the capabilities and capacity of this new vessel,” Berger said.

 He acknowledged that the price had increased significantly from GLDD’s initial estimate of $94 million. GLDD has also settled its dispute with Signal and received a $10 million settlement.

The tug’s main propulsion will come from two MAK 12M32C-T3 diesel engines, producing 7,831 hp each, connected to Schottel props through Overton Chicago marine gears. The MAKs will also power twin shaft generators each rated at 2,500 kW, 6,600 VAC. The tug will also be equipped with a Caterpillar C32-T3 powered auxiliary generator, producing 730 kW of electrical power at 1,800 rpm, and a Cat C18-T3 550-kW emergency genset.

The tug will be ABS classed Maltese Cross A1, AMS, ACCU, Oceans Towing Vessel Unlimited Service, ILO, SOLAS/IMO/MARPOL and USCG certified Dual-Mode ITB, 33/46CFR, Subchapters E, F, G, I, J, M, Q and S.  

The barge, GLDD151, will have a hopper capacity of 14,920 cu. yds. and will be fitted with twin Schottel STT2 electric, fixed-pitch bowthrusters, producing 800 hp each, powered by generators on the tug. The dredge pumps will be powered by two, 5,000-hp EMD ME20G7C-T3 diesel engines on the barge.

GLDD151 also will carry a Cat C32-T3 powered harbor service genset, sparking 910 kW at 1,800 rpm.

The dredge will be classed ABS Maltese Cross A1, AMS, Unmanned Cargo Barge and SOLAS/IMO/MARPOL certified. In addition, it will be USCG certified 33/46CFR NVIC Publications, Subchapter I, Unmanned.

The tug and barge will be connected by a Taisei coupler system.