A submarine bursting through the Arctic ice is a powerful image. But it’s not an easy one to pull off.
“The arctic environment is very unique and presents numerous challenges,” Commander Tommy Crosby told Popular Mechanics . “Our focus is to ensure we conduct every surfacing safely and effectively.”
The Arctic is a convenient hiding spot, since sea ice provides submarines with cover making them almost impossible to detect from the air. However, that same sea ice makes communicating (or launching missiles ) impossible, which means sometimes subs must crack through the ice with several thousand tons of steel. Busting through Arctic ice is a “keep your hands and arms inside the vehicle” kind of maneuver. The U.S. Navy practiced these sub-zero maneuvers the past few weeks at the ICEX 2018 , a biennial exercise in the Arctic. The British submarine HMS Trenchant joined forces with America’s Seawolf-class USS Connecticut and Los Angeles-class USS Hartford in a dress rehearsal for competing in this thawing theater of war.
Breaking through thick Arctic cover is so hard on a vessel that a submarine commander’s first task may be to avoid punching through ice altogether. A sub that needs to surface can try to find open water with the help of a tool provided by the National Ice Center . It’s called the Fractures, Leads, and Polynyas (FLAP) analysis, and this tool predicts where open water can be found in frigid areas.
A simple fracture means any type of crack found in the ice. A lead is one big enough to accommodate a submarine. These are usually created by divergent ocean current flows or wind pushing the ice sheet apart. A polynya , a term borrowed from Russian, means a spot of open water that’s surrounded by ice but doesn’t freeze over. This phenomenon occurs because of an upwelling of warm water or a melting effect caused by coastline. Any of these can provide favorable conditions for any surfacing sub.
The FLAP analysis uses satellite imagery and predictive software to forecast several days ahead of time where there will be open water. A sub gets this report before it disappears under the ice, out of radio communication range, to get details of the open water it is likely to occur during the mission.
But if no open water or fractures can be a found, a submarine crew moves on to plan B.
Typicals submarines can break through about three feet of ice. Vessels that have been specifially strengthened can go through about nine feet. Even so, one careless move could damage a $1 billion sub and put the lives of 100-plus crewmembers at risk. So choosing the right spot is key.
“U.S. Navy submarines use systems such as sidescan sonar, conductivity, temperature and pressure detectors, and a Submarine Remote Video System to help select the best location for a submarine to surface through ice,” Crosby tells Popular Mechanics .
That last tool is the one that provides the final check before a submarine attempts a breakthrough. This video system is a […]