Ice-savvy tugboat crews keep cargo moving in Alaska
Capt. Mark Theriault throttled up on Stellar Wind’s twin Caterpillar engines but the tugboat stayed firmly in place, its rounded bow pressing against a terminal at the Port of Alaska near downtown Anchorage. The real action was off the stern, where prop wash from the Rolls-Royce z-drives smashed, shattered and otherwise dispersed surface ice up to 6 inches thick.
The cargo ship Matson Kodiak was approaching with a load of hundreds of shipping containers, and Cook Inlet Tug & Barge crews were busy clearing ice so the vessel could dock. Over radio, the pilot from the Southwest Alaska Pilots Association asked about ice conditions at the pier.
“It’s starting to separate a little bit,” Theriault said, adding that there was more work to do.
“OK, so just starting to get it off the dock. Roger,” the pilot responded.
Ice management is something that tugboat crews in much of the United States probably never consider. But it’s an integral part of the job for those working around Anchorage and Cook Inlet, where ice usually arrives in November and can last into May. It’s just one challenge in a region home to the largest tides in the U.S., frequent storms, bitter cold and some of the longest nights anywhere.
Glacier Wind sweeps from north to south along the dock face at the Port of Alaska to create a pocket of open water. Sea ice can prevent ships from docking flush against the terminals, which can hinder the loading and unloading of cargo.
“It’s a very unique environment,” said Theriault, a New Hampshire native who has spent 14 winters in Cook Inlet. “We talk a lot with captains who work in other places. They aren’t interested in being here when the ice shows.”
About a half-hour earlier on this February day, Theriault backed the 3,500-hp Stellar Wind off the company platform in Cook Inlet and turned north toward the port. Sunrise came at about 0900, and by 1030 the temperature had risen to 3 degrees — relatively cold even for Anchorage standards.
Two other tugs, the 2,450-hp Glacier Wind and 3,300-hp Daniel Foss, departed moments earlier from the dock located some 250 yards into Cook Inlet. Daniel Foss is on long-term lease to Cook Inlet Tug & Barge from Foss Maritime, which bought the company in 2011.
There are three major types of ice in Cook Inlet, named for British explorer Capt. James Cook, who came looking for the Northwest Passage in the late 1700s. Surface ice shifts with the wind and tide and never stops moving; it is typically no match for the tugboats’ reinforced hulls and z-drives. Ice pans, sheets that can be 18 inches thick and as large as five football fields, are more serious and can stop line-haul tugs and articulated tug-barges (ATBs) in their tracks. Beach ice also can cause serious damage. These icy masses grow throughout the winter, picking up silt deposited from nearby glaciers. As the season comes to an end, tidal forces break them loose and pull them into the waterway. These chunks can bob like an iceberg or remain concealed just below the surface.
“If it’s just (surface) ice we don’t really have any issues,” Theriault said. “The problem is in the spring. When we have big spring tides it will take all that beach ice (into the water), and some of it will be as big as a Volkswagen or even a dump truck.”
Capt. Mark Theriault has spent 14 winters working in Cook Inlet. “It’s challenging and it’s not the same all year long,” he says of the region known for huge tidal swings and ice that can last from November to May.
Stellar Wind plowed through crusty surface ice resembling a roughly frosted cake en route to the port. The ride was fairly smooth aside from the occasional jolt or vibration. Theriault guided the vessel to the north end of the terminal and aligned the bow against a reinforced pier. It was time to build an “ice shadow” around the terminal.
He pushed the engines to half-ahead. Churning water from the 105-inch props swamped and weakened the surface ice, breaking it apart and pushing it away from the dock. The tugboat’s hull prevented ice moving north to south with the ebb current from encroaching on the terminal.
“We’re going to stay here and run the drives,” Theriault said of the process. “That clears up the ice, and the tug holds it at bay on the port side.”
Glacier Wind and Daniel Foss reached the port soon afterward. The two tugs lined up with their bows facing the terminal and slid from north to south along the dock face. Their engines broke up ice while their hulls swept it aside, creating a pocket of open water for the incoming ship.
Large vessels like Matson Kodiak and TOTE’s roll-on/roll-off (ro-ro) ships that call on Alaska can operate in surface ice. But heavy ice buildup around the terminal can prevent them from landing flush against the dock. This prevents shoreside crews from accessing outer cargo boxes.
Engineer William Clock stands alongside one of Stellar Wind’s twin Caterpillar 3512 diesels. The tug, built in 1993, also is equipped with Rolls-Royce z-drives.
The terminal was almost ice-free after Glacier Wind and Daniel Foss finished their first few sweeps. Every so often, small pieces slipped past the blockade set up by Stellar Wind, only to be corralled by the two other tugs.
“See those chunks over there? We don’t like to see them,” Theriault said.
Alaska is a challenging environment for workers, even for people who don’t mind the weather, said Port of Alaska spokesman Jim Jager.
“We’re not the only port in the world that gets a lot of ice, we’re not the only port in the world that has big tidal switches, and we’re not the only port in the world that has a huge sedimentation issue,” he said. “But when you combine all of those things … we are highly unusual.”
Anchorage has the second-largest tidal range in North America after the Bay of Fundy. The tidal range in Cook Inlet, which links the city to the Gulf of Alaska, can be as much as 40 feet, according to the National Oceanic and Atmospheric Administration. Most ships, line-haul tugs and ATBs typically try to time their arrival and departure with the tide.
Glacier Wind, left, and Daniel Foss return to the Cook Inlet Tug & Barge dock through crusty surface ice up to 6 inches thick. Ice pans and beach ice present more of a navigational challenge.
“When you travel with the ice, you have to travel with the tide,” said Cook Inlet Tug & Barge CEO Ben Stevens, a former tug captain for Kirby and other companies. “If you’re meeting an incoming ship at low water, you can ride with the ice. But if they don’t, because the fuel barge is so heavily laden, you can’t buck the ice and the tide at the same time. They can’t make any way.”
Ships like Matson Kodiak that land starboard to the terminal often try to arrive just after high tide to keep the current from pushing on their sterns, Theriault said.
The port maintains a 35-foot depth at mean low tide, which requires nearly nonstop dredging during the summer months to clear sedimentation from nearby rivers and glaciers. Even during the winter, when dredges can’t operate, local tugs use their prop wash to blast away sediment from the terminal.
“The silt is from the glaciers and rivers. It is called glacial milk. It is essentially finely ground rock,” said Jager. There’s so much sediment, he added, that kayakers can hear the silt whooshing against their hulls.
Glacier Wind met Matson Kodiak about a mile off the terminal. The tug’s crew got a line onto the port shoulder and remained alongside. Daniel Foss arrived a few minutes later and took position on the ship’s port quarter. Stellar Wind remained against the terminal to keep the ice shadow in place.
Stellar Wind assists Matson Kodiak into newly opened water at the Port of Alaska.
Matson Kodiak’s pilot approached the dock at an angle to keep from dragging ice into the berth, then lined up starboard to the dock. The pilot guided the ship toward the terminal using its thruster and support from the tugs. The docking evolution was clean and straightforward.
Stellar Wind kept the ice shadow in place until the mooring lines were tight. Otherwise, ice moving with the current could wedge the ship out of place. “If (we) pulled away right now, this whole thing would slide down the face of the dock,” Stevens said of ice corralled against the tug’s port side.
Stellar Wind is the most powerful of the three Cook Inlet ship assist tugs. It was built in 1993 by Tri Star Marine of Seattle and can handle icebreaking, escort and ship docking. Propulsion consists of twin Caterpillar 3512 mains turning Rolls-Royce z-drives. Theriault said the tug is powerful, maneuverable and “can do anything.”
Theriault worked for five years as a mate on Alaska’s North Slope, home to the state’s most productive oil fields, before joining Cook Inlet about 15 years ago. He has come to appreciate working in and around Anchorage.
“It’s challenging and it’s not the same all year long. I like the challenges of the current and the ice and the combination of both,” he said.
Deck hand Pieter Vanderhoek ties a line onto Daniel Foss at the Cook Inlet Tug & Barge platform in Anchorage. The company’s tugs in the port are manned around the clock.
Cook Inlet and its sister company, Anderson Tug & Barge in Seward, Alaska, have harbor and fuel divisions that collectively employ 64 mariners. The harbor crews can choose between one- or two-week turns, and at any given time there are 24 harbor tug crewmembers available in Anchorage and Seward.
“Two weeks battling in this in the wintertime is long enough,” Stevens said. By then, Theriault added, “It’s time to go.”
Cook Inlet’s Anchorage tugs are manned 24 hours a day, often with a three-person crew. Engineer William Clock and mate Justin Ryan accompanied Theriault on this day aboard Stellar Wind.
After finishing with Matson Kodiak, the three tugs returned to the company dock. Theriault made a couple of passes alongside the platform to break up a nuisance ice pan that blocked its path. The other tugs arrived soon afterward and tied up at the dock.
The next job wasn’t scheduled for about 18 hours, when the company’s tugs would help reposition Matson Kodiak for its outbound run. Not far behind it, a TOTE ro-ro ship was due after a daylong weather delay. Whenever it arrived, Cook Inlet’s crews would be ready.