On Friday last week, the American submarine USS Seawolf surprised many when surfacing in Tromsø, Norway. The US Navy reports that there was a brief stop for personnel reasons.

According to the US Navy, the Seawolf-class submarines are exceptionally quiet, fast, well-armed, and equipped with advanced sensors. Though this class of submarines lacks vertical launch systems, it is armed with eight torpedo tubes and can hold up to 50 weapons in its torpedo room.

The Pacific-based submarine is operating in U.S. 6th Fleet to compliment the undersea warfare capabilities of U.S. Naval Forces Europe.