Why Arctic anti-submarine surveillance still depends on submarines

Should the United States and Canada use sonobuoys or towed-array icebreakers to monitor a more contested Arctic?

Seabed sensors and submarines are more practical; moving ice makes an icebreaker's towed array especially vulnerable.

A towed array behind an icebreaker risks being trapped or damaged as the ice closes after the ship passes. Fixed hydrophones and seabed acoustic networks avoid that immediate problem, though their existence and coverage may not be public. Until the Arctic becomes substantially more ice-free, the most reliable way to contest hostile submarines is to send submarines of one's own. Canada's Upholder-class purchase suited this mission because those boats could sit beneath ice and listen, despite the maintenance problems inherited with them.