(60) marine technology April 2016 www.sname.org/sname/mt

VESSEL REPORT: ARCTIC CLASS TUG

VESSEL REPORT

F oss Maritime is continually looking to develop its fleet of tugs to meet the demands of new markets in marine transportation services. Starting in 2005, Foss chose to focus heavily on the expand-

ing offshore oil and gas industry in the Arctic.The Arctic is an ever-changing market, with unique

conditions and challenges. The leadership of Seattle-based Foss knew that, to thrive in the far north, their vessels would need substantial power and ice capa-bilities, while maintaining the company’s reputation for safety and environmental stewardship. For its new class of tugs, Foss looked to longtime partner, Glosten, to fulfill these mission requirements—from concept through complete detailed production design.

The partnership was a natural choice. Foss Maritime has more than 120 years of experience in northwest towing and marine logistics, while Seattle-based Glosten offers expertise in integrating complex technologies into efficient, practical marine systems.

Foss and Glosten have worked as partners since 1958 on projects ranging from tugs and barges to aerospace transportation and international logistics projects.

The team’s challenge was to improve opera-tional and environmental performance in a cost effective way. Glosten led the technical engineer-ing and design effort, and Foss acted as the overall project lead, construction lead, and ultimately the vessel owner/operator. The result was Foss’s Arctic class tug, a 132-ft. vessel with more than 7,300 hp. delivered by two Cat C280-8 engines, and producing 100 metric tons of bollard pull through two Nautican propulsion units.

Collaborative constructionWith only Foss and Glosten as project stakeholders, the team laid the foundation for a collaborative and efficient program. Glosten Project Manager William Moon, III and Foss Project Manager Dan Cole (who also is co-author of this article) were co-located and in constant contact from early in the design stage through testing and trials. This enabled quick reso-lution of design issues as they arose. “This project embodied the collaborative relationship we strive for in all of our design projects,” says Moon. “When the designer and owner are in constant contact, and you have operations input early in the design, you know you’re going to have a great end product.”

Evolving the contract design in parallel with the func-tional design and lofting—a first for Glosten—enabled the

Michele Foss was delivered in May 2015 and embarked on her first Arctic mission over the summer, delivering

gas refinery modules from Ulsan, Korea to Point Thomson, AK.

BY JAY EDGAR AND DAN COLE

The main deck tow gear includes a 200

metric ton shark jaws, tow pins, and split

stern rollers, all provided by Smith Berger.

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project team to stay on top of Foss’s desired schedule. The Glosten team led weekly 3D reviews of the production design with the Foss design, lofting, and shipyard leads.

Glosten’s production team lofted the vessel in its entirety, including structure with pre-cut penetrations, structural outfit, all distributed systems, pipe spools, HVAC ducting, and electri-cal trays. The operational requirements to meet safety standards and ABS Arctic class drove the complex structural arrangements and piping systems. Glosten’s Production Services team integrated the Foss shipyard’s needs into their deliverables and maintained consistent and clear communications. Their collaborative style provided added value to the project.

Three dimensional modeling early in the design cycle and of the final structure and systems not only improved the production of the vessel, but verified sightlines, maintenance envelopes, and interior spaces all resulting in improved crew safety and com-fort. The two-party collaboration avoided the kind of schedule delays that can be common on this type of project due to bid-ding and contracting. The Foss/Glosten team maintained the desired schedule for the phased three-vessel build program at the Foss Shipyard in Rainier, OR—the yard’s largest and most complex build to date. As part of Glosten’s construction support phase, the production team incorporated as-built drawings in the ShipConstructor model for the subsequent vessel programs.

In 2015, the project team completed construction of Michele Foss, the first of three ice-class tugs to be built at the Foss Rainier shipyard, and delivered it for integration into the Foss f leet. Michele Foss set out on her first Arctic mission over the sum-mer, delivering gas refinery modules from Ulsan, Korea to Point Thomson, AK.

Harsh environmentsTo satisfy the identified market, the vessel was designed to tow large barges and ships on coastal and ocean routes worldwide. The team worked closely to develop a vessel mission statement that included operational and maintenance needs and focused on safety and capabilities, while defining performance capabili-ties. These included bollard pull, endurance, and seakeeping, along with specific requirements such as regulatory, deck machinery, accommodation, and safety systems.

The towing winch and the propulsion engines served as the centerpieces of the vessel design. Foss selected longtime winch partner Markey Machinery to provide a custom double drum winch, with a water-cooled slip brake and below-deck diesel power. The main deck tow gear includes a 200 metric ton shark

jaws, tow pins, and split stern rollers, all provided by Smith Berger. The winch is under-wound and when combined with the flush deck stern roller and tow pins, provides a much safer environment for the crew. The winch’s slip brake significantly reduces the chance of a broken tow wire by shaving off the peak tensions experienced in rough ocean tows.

Caterpillar C280-8 engines were paired with Reintjes reduc-tion gears and Nautican integrated propulsion units to achieve the 100 metric ton bollard pull requirement, all while minimizing fuel consumption at towing speeds. The Nautican units (including high efficiency nozzles, propellers, pre-swirl stators, and triple rudders) were combined with a hull of proven performance to exceed the design goals of efficiency and sea-kindliness.

The tug was designed to minimize lifecycle cost and reduce maintenance from the initial hull form development through the fabrication sequencing and detailing. Reduced maintenance was supported through such things as the use of closed bulwarks, no external manholes, stainless steel external piping, and minimizing salt water onboard the vessel. The elimination of ballast tanks pre-vents the possible transporting of invasive species and Fernstrum keel coolers help keep corrosive seawater out of the boat, helping to maximize the life of the vessel.

Michele Foss features a custom double drum winch by Markey Machinery, with a water-cooled slip brake and below-deck diesel power.

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Arctic Class Tug Michele Foss

Environmental features of the vessel include an efficient pro-pulsion system; no ballast water; holding tanks for black and gray water; energy efficient LED lighting; biodegradable hydraulic oil; a hazardous construction materials tracking system for responsible maintenance and disposal of the tug at the end of her operating life; and an impressed current cathodic protection system, which pro-tects the steel hull from galvanic corrosion. Additionally, the hull has wing void tanks, a SOLAS compliant double bottom, and seg-regated main and auxiliary machinery to increase the survivability of the vessel and minimize the risk of pollution. The 150,000-gallon total fuel capacity is protected with an overflow system, virtually eliminating the risk of spilled fuel at the dock.

The tug incorporates many features necessary for cold weather operations such as heavy scantlings and a reinforced hull, rein-forced drivetrain, and redundant and independent port and starboard steering. Additionally, Foss included fresh water tank heating; enclosed bulwarks; wing voids around all machinery and fuel tanks; a fully covered main winch; and exterior machinery heating. All of these help ensure safe and reliable operations in frozen waters.

This powerful class of vessels, designed to withstand the rig-ors of arctic operations, has become the new flagship for Foss

as they compete for emerging opportunities in the offshore oil and gas industry. Glosten continues to support the construction of the next two ice-class tugs. Construction of the second tug, Denise Foss, is underway, with the third scheduled to begin in spring 2016. MT

Jay Edgar is president of Glosten. Dan Cole is project manager at Foss Maritime Company.

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Vessel Report continued

SPECIFICATIONS: ARCTIC CLASS TUG

OWNER Foss Maritime Company

BUILDER Foss Rainier Shipyard

DESIGN Glosten

DELIVERED May 2015

CLASSIFICATION ABS A1 Towing, AMS, ABCU, Ice Class D0

TYPE Arctic tug

MAIN PARTICULARS

LENGTH OVERALL 132 ft.

BREADTH 41 ft.

DEPTH 20 ft.

ENGINES Two Cat C280-8

HORSEPOWER 7,268

PROPULSION MGO

TOW WINCH Markey double drum TDSD-40

BOW WINCH Markey WEWD-22

FIRE PUMP Two Flowserve units, 10 hp.

This rendering overlay shows internal piping and structure of Michele Foss.

A 3d product model of Michele Foss rendered in ShipConstructor.