“Snorting” describes the process by whichsubmarines rise to the surface of the ocean – similar to whales blowing – to expel contaminants,replenish their oxygen supplies and recharge batteries. Diesel-powered submarines like Australia’s current Collins-class vessels have to snort regularly to continue to operate.
The problem with snorting (also known as snorkelling) is it allows submarines to be detected by other nations’ radar and sonar systems,making them vulnerable to attack. The attribute that gives submarines a crucial advantage over ships – their stealth – suddenly disappears.
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Until now,submarine captains have gotten around this problem by replenishing their vessels’ batteries away from operational areas,after dark and during bad weather. The tactic is known colloquially as “going out to snort in the bushes” (a term that may bring other legally questionable land-based activities to mind).
But rapid advances in radar detection and artificial intelligence are making it easier for other militaries to detect even brief “snorts”. As Marles said on Tuesday,the increased ability for “the process of snorting to be detected” explains why the current Collins-class submarines are becoming obsolete for Australia’s needs.
This problem doesn’t apply to nuclear-powered submarines given their generators don’t need oxygen,allowing them to stay submerged for months at a time and only needing to surface to restock food.