Before the Navy lets anyone drive a multibillion-dollar submarine, it makes sure they know everything there is to know about handling it. But one skill not in the regular curriculum is how to surface straight up through a heavy sheet of ice.
"The vertical surfacing procedure is not a technique that is part of the normal submariner's skill set," Cmdr. Cameron Aljilani, commanding officer of Seawolf-class fast-attack submarine USS Connecticut, said during an interview at the end of May.
Aljilani spoke a few months after the USS Connecticut and Los Angeles-class attack sub USS Toledo took part in Ice Exercise 2020, the latest installment of a biennial Navy exercise meant to test the sub force's ability to operate in the harsh Arctic environment.
Perhaps the most well-known feature of that exercise is a sub surfacing through a layer of ice.
"Normally we would ascend to periscope depth having speed in the water," Aljilani said. "Due to under-ice operations, you can't be moving forward. You have to go up at zero speed and straight to the ice. That's one thing that we would practice."
Sea ice provides concealment for subs, shielding them from aircraft. But subs have to punch through that ice to communicate, launch missiles, or support surface activity like that which takes place during ICEX.
The US's three Seawolf-class subs, designed near the end of the Cold War and still considered the most capable in the Navy, have a hardened sail that can break through thick ice, a feature that has been included on newer Virginia-class subs, Aljilani said.
"Each class of submarine has the ability to service through a certain thickness of ice, and so we had to identify where the right thickness was," Aljilani said.
Subs also have different types of sonar as well as other sensors and video systems to assess ice overhead. Upward-looking sonar allows the crew to locate the ice canopy in relation to the sub and find patches of open water or areas of minimal thickness.
"We can tell with the sonar how far the ice protrudes down," Aljilani said. "While we can surface, there's a maximum amount of ice we can surface through. It's not good to slam your submarine through ice, and so we try to find areas of minimal thickness."
Once a promising spot is found, the sub sails a cloverleaf or racetrack pattern while it figures out how big the area is and how thick the ice is there.
The area "has to be of a certain size," Aljilani said. "The ship drifts with the underwater current, but also the ice drifts, so you've got two pieces that are moving ... so you have to make sure you have an area that's large enough that the submarine can surface in it and get the sail through the ice."
Once the crew finds the center of the area they want to surface in, the sub will stop, hovering as it prepares for vertical surfacing.
"Once we stop the ship, then we will set our compensation tanks, or trim tanks, and we'll start pumping out water to make it less buoyant and get a certain ascent rate, and we'll pop through the ice. We need a certain speed and momentum to break the ice," Aljilani said.
Guidance from the National Ice Center helps subs find places to break through. Arctic operations specialists from the Navy's San Diego-based Arctic Submarine Lab, the lead organization for ICEX, also provide information needed to determine where and how to surface — knowledge they acquire through years of experience on different classes of subs, Aljilani said.
Arctic Submarine Lab founder Waldo Lyon was the ice pilot aboard USS Boarfish when it conducted the first transit under an ice floe on August 1, 1947. USS Skate carried out the first Arctic surfacing in March 1959.
A video from the Hartford during ICEX 2018 illustrates the surfacing process and what it's like inside the sub:
Once surfaced, sailors can go onto the ice and visitors can board. Sens. Gary Peters and Tom Cotton and Reps. John Garamendi and Bill Foster were among the Connecticut's guests during ICEX 2018.
This year, with the exercise taking place amid the coronavirus pandemic, health-screening protocols were put in place for people moving on and off the sub, Aljilani said.
The crew also packed the sub with food and spare parts before leaving port, which facilitated endurance tests during the exercise and meant it didn't need to take on additional cargo from the base camp, which was about a mile away from where the sub surfaced.
Under the ice, it's quiet enough for sonar on the sub to pick up a snowmobile on the ice miles away, even with the background noise caused by the movement of the ice, Aljilani said.
Atop the icy expanse, "there's nothing. Just complete silence," Adam Glover, a technician and official photographer aboard USS Hartford during ICEX 2016, told Popular Mechanics in 2018.
But that doesn't mean sailors don't need to be on the lookout.
During an ICEX in April 2003, a polar bear came across the Connecticut jutting through the ice, attracted to an opportunity for food. Mark Barnoff, a scientist working nearby, was touring the Connecticut and took photos through the periscope as the bear examined the sub, gnawing on its rudder.
The bear "wasn't in a rush to do anything," Barnoff told ABC News in 2006. "It was on its own schedule."
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