Arctic Titan: another extraordinary tug for Western Towboat

Jul 5, 2012 10:27 AM
With crew input the tug was designed for efficiency and easy maintenance.

With crew input the tug was designed for efficiency and easy maintenance.

While phrases such as “Go west, young man” have lost their verve, “North to Alaska” is still a vibrant one for Seattle-based Western Towboat. Anticipating steady growth in the Alaska trade, the company is close to completing its sixth Titan class ASD ocean tug, the 120-foot Arctic Titan.

Western’s fleet numbers 19 tugs and its office, shipyard and dock are located on the north bank of Seattle’s Lake Washington Ship Canal, a busy artery lined with commercial fishing boats, recreational marinas, tugboat and coastal shipping companies, shipyards and other industries. There is an artist’s palette of colors lining the canal’s banks, but the blue and golden yellow of Western’s fleet really jumps.

The large soft loop bow fender by Schuyler aids in maneuvering barges.


Since 1982 Western Towboat has built 17 tugs at its yard on the canal. Robert Shrewsbury Sr. founded the company in 1948. His two sons, Robert, Jr. (Bob) and Ric, now serve as president and vice president.

Arctic Titan, as with all the tugs it builds, is an example of a vessel designed for easy maintenance and efficiency. “These boats are laid out by the people who work on them and have to maintain them,” said Bob Shrewsbury.

Arctic Titan is the culmination of applying operation experience and tug-building skill, developed since the 90-foot, 3,000-hp Western Mariner was launched 30 years ago from the newly built yard.

The process, originated by Robert Shrewsbury Sr., is remarkably simple. Bob and Ric consult with the boat crews and shipyard tradesmen and make a wish list for the new boat. Bob works up some preliminary drawings and then they pass the list and drawings on to Jensen Maritime Consultants, where the design is completed.
 

The Western Towboat fleet tied up in Seattle for the winter.

“That hasn’t changed much since then,” said Ric. “We give the numbers to Jensen, and they work up the lines for us. We use stainless on any place that rusts.”

Pointing to the stainless cap rail, hand rails and the aluminum house, Ric explained that stopping rust begins at the design stage. The brothers’ contention is that time saved from tedious tasks is better spent running the boat.

“Their boats last forever,” said Jonathan Parrott, vice president of new design development at Jensen Maritime Consultants, now a part of Crowley.

Parrott has worked on most of the boats that Western has built, fleshing out Bob Shrewsbury’s drawings. “Western is unique in that they build one boat at a time and they can pull people from it if they have to do other emergency projects. They’re not in a rush, and each boat they build is a little bit better than the last one, as they are constantly incorporating lessons learned from the earlier builds,” he said, noting that Ed McEvoy, the port engineer at Western since 1984, considers Arctic Titan the best of the class.

Arctic Titan is powered by two Caterpillar C175 Tier III engines rated at 2,682 hp each, at 1,600 rpm. The mains are connected to Schottel SRP 1515 azimuthing z-drives with four-blade, 104-inch-diameter stainless steel propellers. The estimated bollard pull of the tug is 80 tons and the vessel’s free running speed is 13 knots. Two Caterpillar C9 175-kW auxiliary generators supply electrical power and power for the winches.

Caterpillar supplies the engines for Western Towboat, often with a field follow agreement that allows them to track the engine’s performance for an agreed upon time, usually one year. “They like the hours that we run them,” said Bob. “It’s about 5,500 hours a year and it’s hard towing, so they find out more about the engines than they would just running them.”

Western Towboat, with machinists, fitters, welders, carpenters and diesel mechanics on hand, and a warehouse with parts and spare engines only a stone’s throw from the fleet, is able to swap out engines routinely. The stacks on a Western Towboat tug are bolted, rather than welded, to the upper deck, so that they can be quickly removed for an engine change. “We have a warehouse with swing engines stored and ready to go,” said Ric.

The Rapp Hydema hydraulic winch incorporates an automatic render/recover system that monitors the tension on the line and keeps it constant.


It takes about 30 hours to change an engine. In order not to disrupt the weekly scheduled runs to Alaska, the company’s practice is to change one engine when the boat is in home port, send it out for a run north, and change the second engine when it returns . “We have good people with the know-how to get the job done, said Ric.”

The towing winch on Arctic Titan is a Norwegian made Rapp Hydema Tow-22041 multispeed unit supplied by Rapp Hydema NW. The hydraulic winch incorporates a render/recover system controlled by Rapp’s PTS Pentagon auto-tow system with touch-screen monitoring in the house. The system monitors the cable length, tension and line speed, reeling in or paying out the wire to maintain constant tension. The winch is wound with 3,200 feet of 2.25-inch wire and 3-inch surge chain on a single drum.

The company builds its own Western Towboat headline winches, one of which is on the bow of Arctic Titan, with 150 feet of 2.5-inch plasma line wound on the drum.

Western Towboat’s main business is towing container and railcar barges for Alaska Marine Lines, a division of Lynden Transport. “The bulk of our work is cargo barges to Southeast Alaska, Whittier and Western Alaska,” said Bob. “We have two tugs that leave every Wednesday for Alaska year around, and one tug every Friday from March through December.”
 

One of the two Cat C175 Tier III main engines rated 2,682 hp each. They power Schottel z-drives with four-blade props.

On Wednesdays, Western Titan and Pacific Titan trip to Southeast Alaska ports on an 11- to 12-day run. Ocean Titan, Gulf Titan and Alaska Titan leave every Wednesday for Whittier in Prince William Sound on a three-week rotation, each trip running 15 days in the summer. “But they can be as long as 21 days or more in the winter,” said Bob. “The Gulf of Alaska crossing dictates trip times. We can travel in up to 18-foot seas, but more than that and we have issues with railcar lashings and beating the cargo up. We add a fourth tug and barge to the service in the winter if weather delays the sailings by more than one or two days.”

The company’s Friday service to Southeast Alaskan ports utilizes its conventional twin-screw ocean tugs with propellers in NautiCan nozzles and triple-rudder steering. Ocean Ranger and Ocean Mariner are two such vessels. In the summer, Western also runs three trips with supply barges to the Red Dog Mine, a gigantic zinc and lead mine in northwest Alaska’s De Long Mountains.

The engines are soft mounted to reduce fatigue-inducing vibration.


Many ports in Alaska, especially in the Panhandle, are tight and starkly equipped to handle a barge tow. Often the weather is foul, sometimes more than that. The ocean tugs, with the tow on a wire, have to get the tow stopped, tie up alongside it and maneuver it to its mooring. The maneuverability and omni-directional power of ASD tugs have eased the difficulty and increased the safety of delivering barges to difficult ports without assist tugs.

“When we get up to Alaska, we take the barges alongside and set up a spring line,” said Bob. “We run all the winches on all the boats from up here (in the wheelhouse). “Nobody is working on deck. We’ve been doing it that way since we built our first boat in 1982.”

Auxiliary power comes from two Caterpillar 175-kW gensets.


Schuyler supplied a large soft loop bow fender and a laminated stern fender that wraps around the stern corners of Arctic Titan. The fendering is common on all the Titan tugs and is particularly suited for their work of delivering barges to Alaska ports.

The attention to detail in the interior joinery, the steel work and coatings on Arctic Titan is outstanding, but you would never know that, listening to Bob Shrewsbury. “It’s just another tug. Nothing exceptional going on here.”
 

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