Polar Security Cutter Fuses Performance Requirements With Maintenance Needs

September 16, 2019 7:15 PM
An artist’s rendering of VT Halter Marine’s winning bid for the U.S. Coast Guard Polar Security Cutter. VT Halter Marine image used with permission

WASHINGTON, D.C. – By building a heavy icebreaker designed to both withstand the frigid waters and accommodate major maintenance needs, the Coast Guard hopes to avoid the catastrophic failures that have hamstrung the service’s polar missions for a nearly a decade.

The Polar Security Cutter’s builder VT Halter Marine teamed up with New Orleans-based Technology Associates Inc. to focus on creating a cost-effective design that is flexible enough to accommodate new technologies, changing missions and complicated repairs. The Coast Guard awarded the $745.9 million contract to build the Polar Security Cutter in April and delivery is expected in 2024.

“We deliberately looked at how workers can get into spaces to fix components at sea,” said retired Marine Corps Brig. Gen. Ronald Baczkowski, now chief executive of VT Halter Marine, at last week’s American Society of Naval Engineers Arctic Day 2019 conference.

An example of how the icebreaker’s design and build teams weighed the placement of major components and which materials to use is the Polar Security Cutter’s engine space, said Anil Raj, the president of Technology Associates, at the conference. For inspiration, the designers looked at the Coast Guard’s current fleet of heavy icebreakers,  

The Coast Guard’s ability to run Arctic and Antarctic missions has been hampered since June 2010, when USCGC Polar Sea (WAGB-11), one of the service’s two heavy icebreakers, suffered a catastrophic engine failure.

The cost of repairing Polar Sea would be astronomical to consider, Raj said. Its engine is buried in the ship, and the exotic high-strength steel used to build Polar Sea’s hull hasn’t been made in decades. Accessing the engine for repairs would mean cutting a hole in the hull with no realistic way to patch it when finished. Instead, the Coast Guard ‘s other heavy icebreaker, USCGC Polar Star (WAGB-10), remains operational by cannibalizing parts from Polar Sea.

“We said ‘that cannot be repeated’,” Raj said. “It was not part of the spec requirements, but it was something we wanted to rethink. We put our engines up high, and you can actually pull the block up through the stack if you had a catastrophic failure.”

The Polar Security Cutter will have split stacks, which provides the bridge a view of the helicopter pad in the aft of the ship, Raj said.

The type of steel used to build the icebreaker is also significant. Instead of using an exotic steal, VT Halter is using a kind of steel commonly rolled in the U.S., Baczkowski said. The design uses mostly flat plates with some compound curves, limiting the amount of forging and casting and saving on production costs.

A unique attribute of the Polar Security Cutter is the length of its midsection, Raj said. Compared to other heavy icebreakers, the Polar Security Cutter is longer than most because its mission requirements are different. The Polar Security Cutter will be 460-feet long. In comparison, Finland’s new IB Polaris heavy icebreaker is about 360-feet long, according to its builder Artia.

“An icebreaker shouldn’t have a long mid-body. That’s true for Baltic icebreakers, that’s true for the Russian icebreakers that have to keep the sea lanes open,” Raj said. “But that’s not necessarily true for the icebreaker that has to travel 9,000 miles to reach its target and keep the people comfortable and needs to carry the fuel to get there. So, you can see that we have a long body.”

The lengthened hull allows the Polar Security Cutter to do open water missions and has free space that could be used in the future for science missions, Raj said. The Coast Guard specs called for an icebreaker that could handle sea state four, marked by between 4-foot and 8-foot swells. Raj said the VT Halter and Technology Associates design has the icebreaker handling up to sea state 7, marked by a stomach-churning 20-foot to nearly 30-foot waves.

The Polar Security Cutter’s primary mission is breaking thick ice so cargo ships can bring supplies to the harshest harbors on Earth, such as the National Science Foundation’s research facility, McMurdo Station, in Antarctica.

VT Halter and Technology Associates team researched several heavy icebreakers, using one, two and three propeller pods for propulsion, Raj said. They settled on using two ABB Azipod V3000 pods and one standard propeller to give the icebreaker a combination of power, stability and maneuverability.

“The propellers are trying to eat the ice,” Raj said. “It’s basically like a blender on a margarita machine.”

Older icebreaker designs focused on protecting the propellers from ice, Raj said. Now, the materials used to build propellers have improved to the point that propellers are part of the icebreaking process.

“An interesting element of the icebreaker that us naval architects don’t really realize, this whole thing is steel, it’s really one big battering ram of steel and engines and propellers, and the rest is just fuel and mission,” Raj said. “So, concentrating on the steel element is an important portion of it.”

Ben Werner

Ben Werner

Ben Werner is a staff writer for USNI News. He has worked as a freelance writer in Busan, South Korea, and as a staff writer covering education and publicly traded companies for The Virginian-Pilot in Norfolk, Va., The State newspaper in Columbia, S.C., Savannah Morning News in Savannah, Ga., and Baltimore Business Journal. He earned a bachelor’s degree from the University of Maryland and a master’s degree from New York University.

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