Page 27: of Marine News Magazine (November 2023)

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Power & Propulsion not subject to speci? c IMO decarbonization measures such pair of Cat 3512E’s, each rated at 2,213 bhp, driving a Schot- as the Carbon Intensity Index, or CII), stressed that “due to tel SRP 430FP Z-drive unit. The same yard has two tugs un- signi? cant inherent differences in vessel categories and their der construction for Moran Towing; also with a Robert Allan operating conditions, there is no ‘one-size-? ts-all’ approach to design, set for 2025 delivery. Most recently, Gulf LNG Tugs future low- and zero-carbon marine fuels.” At the SHIPPIN- (a tie-up of Bay-Houston, Suderman & Young, and Moran

GInsight 2023 Conference, held in mid-October, Jennifer Towing, announced that it would be ordering a quartet of

States, the VP and chief strategy of? cer of the BSMC, pointed Robert Allan designed escort tugs with Z-Drives and Cat Tier to efforts in aviation, where carriers and government set a goal 4 3516e propulsion- two each from Master Boat Builders and of creating one fuel for the industry. States, with a background two from the Sterling yard, in Port Neches, Texas. that includes work at Class society DNV, noted that “The in- The public sector is also moving to Tier 4 boats. In Sum- dustry is working with government to help direct the research, mer, 2023, the Tennessee Valley Authority (TVA, which development and deployment that’s needed for sustainable moves powerplant components by barge) took delivery of aviation fuel [in an effort dubbed ‘Grand Challenge’]…I Freedom, a towboat built at the Vessel Repair yard in Port would say we need a sustainable maritime fuel.” Arthur and powered by a pair of Tier 4 certi? ed Caterpillar 3512E engines.

EPA Tier 4

Alternatives to traditional diesel

In the absence of a grand plan, the course will continue to be charted by rules and regulations. The movement to EPA Hybrid propulsion, where multiple drivers provide the

Tier 4 engines had been slowed as manufacturers struggled power to turn the propeller, are also playing a role. In 2022, to produce engines meeting EPA rules, promulgating fur- Master Boat Builders had delivered two ship escort tugs with ther reductions of NOx and particulate emissions. Tier 4 a Robert Allan Ltd. design, Spartan and Titan, to Seabulk plant technology is typically accomplished using a selective Towing. The vessels, with Berg Z Drive azimuth thrust- catalytic reduction (SCR) after-treatment to pull out NOx, ers, can operate on either Tier 4 certi? ed engines (2 x Cat or, alternatively, exhaust gas recirculation (EGR). 3512E) or on diesel generators (also from Caterpillar). The

Recent deliveries of Tier 4 vessels have included McAllister Lake Charles and Port Arthur operations of Seabulk Towing,

Towing’s Jane McAllister, a Washburn & Doughty-built trac- where the two vessels have been operating, will be sold to Bay tor tug powered by a pair of Caterpillar 3516E engines (us- Houston Towing, in a deal expected to close in late 2023. ing the SCR process) that will be handling ship assists in the Electri? cation will be playing a big role in decarbon-

Norfolk, Va. Crowley Maritime recently took delivery under ization. Kirby Corporation, a leading participant in the long-term charters of a trio of Tier 4 tugs, which will be serv- U.S. maritime sector, discussing its efforts, has said that: ing the West Coast. The boats use a design from Vancouver, “Testing out alternative fuels, ? nding operational ef? cien-

B.C.’s Robert Allan Ltd., and were built at Diversi? ed Ma- cies, and investing in new technologies are a few initiatives rine in Portland, Ore. for Brusco Tug, which then delivered the company is exploring to accomplish its [sustainability] them to Crowley. Summer 2023 saw the delivery of Artemis targets” with a focus on “a 40% reduction of carbon emis- to Crowley, which will use the vessel (powered by a pair of sions per barrel of capacity by 2040”. In late August, Kirby

Caterpillar 3156Es, putting out 7,000 hp) for ship assist and christened its Green Diamond, which it described as “… escort work. Earlier, sister vessels Athena, Apollo and Her- the nation’s ? rst plug-in hybrid electric inland towing ves- cules had been delivered to Crowley under similar arrange- sel,” with battery power capability. ments, and the vessels ate operating under long term charters. Kirby’s Green Diamond is on time charter to a Shell USA

Suderman & Young Towing, based in Houston, has also subsidiary, operating locally in the Houston area. Another taken delivery of several Z-Drive tugs operating in Texas Shell entity, Shell Energy Solutions, installed a plug-in ports. The Eva, Brizo and Aurora are based on the Rapport charging station utilizing kit from Zinus- well known for 2600 design from Robert Allan Ltd., and built by Master Boat providing shore power in the passenger sector, at Kirby’s

Builders Inc. in Coden, Ala. The tugs also are powered by a Old River Fleet Dock, in Channelview, where the towboat www.marinelink.com MN 27|