The attack submarine HMS Trenchant has joined US submarines in the Arctic for ICEX 2018, military exercises involving practice with dummy torpedo attacks and navigation and surfacing through the ice cover. The sea ice provides almost perfect concealment for submarines but brings problems too.
While the upper surface of the ice is smooth the underside is ridged with keels extending downwards for many metres and creating a dangerous collision hazard.
This uneven ice surface also scatters sonar, sometimes producing phantom images and confusing navigation. From a submarine, the ceaseless creaking and groaning of the shifting pack ice above takes some getting used to; worse, the high-pitched sounds can interfere with sonar reception.
The military submarines use sonar to measure the thickness of the ice, helping to validate scientific models of how the cover has changed over the years. Records from similar expeditions, gathered to help identify spots where the ice is thin enough for submarines to surface, have proved a valuable resource for scientists.
The Arctic may be spectacular and fascinating but it is a dangerous place for submarine operations. During the mission ICEX 2007 two sailors died in an explosion on board the Royal Navy nuclear submarine HMS Tireless. The Trenchant’s crew laid a wreath for them last week.
- This article was amended on 22 March 2018, to change “ice sheet” to “sea ice”.
