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Wednesday, November 27, 2019 

Bisso Towboat, located in Luling, LA, USA, recently announced the delivery of its first EPA Tier 4 Final and Subchapter M azimuth stern drive (ASD) tractor tug.

At 6,008 bhp, Andrew S is the most powerful Tier 4 tug on the Mississippi River. Caterpillar Marine supplied two Cat 3516E Tier 4 main engines, each generating 3,004bhp at 1,800 rpm and a selective catalyst reduction (SCR) system. It was built at Main Iron Works, and is the 13th tug in the Bisso fleet, eight of which are of ASD type.

To become both EPA Tier 4 Final and Subchapter M compliant, and meet increased power requirements, Bisso’s team strategically worked with several companies. Caterpillar Marine Territory Sales Manager, Charlson Smith, collaborated with Bisso to select the engine package for the Andrew S. “Our 3500 series engine is compact and reliable. Five of Bisso’s tractor tugs have 3516s in them already,” said Smith.

The Andrew S measures 100ft x 38ft x 13.5ft and has an estimated bollard pull of 84 tons. Additional features of the tug include US Coast Guard-approved engine room monitoring and fire/alarm systems, a fixed CO2 fire extinguishing system, and both the engine room and crew quarters have soundproof insulation. The tug is equipped with a Cat SCR system.

“Caterpillar developed the SCR system we use in the new 3500E series. Cat SCRs have stood the test of time and durability in off-road vehicles, highway trucks, and heavy equipment. The system utilises diesel exhaust fluid (DEF), a urea-based fluid that is mixed with the engine’s exhaust, causing a chemical reaction that significantly reduces NOx in the exhaust. At the same time, the new Cat 3500E series engines maximize performance while increasing fuel efficiency. When the Bisso team saw how the engine performs, they were impressed,” said Smith.

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