Last month, the Norwegian Frigate Helge Ingstad collided with a much larger tanker ship in a Norwegian fjord. Unlike previous high-profile incidents involving U.S. Navy vessels colliding with civilian ships, however, the Helge Ingstad quickly found itself taking on too much water for its onboard pumps to manage. As a result, the $400 million frigate was lost to the sea.

Recovery operations for the Helge Ingstad, November 28, 2018. Norwegian armed forces photo.

With a displacement of 5,290 tons and a length of about 442 feet, the Norwegian frigate is slightly smaller than the Arleigh Burke Class guided missile destroyers of the U.S. Navy that were involved in similar collisions last year, but either would have been dwarfed by the massive oil tanker that collided with the Helge Ingstad. It was reportedly fully loaded with a total displacement of around 113,000 tons — making it heavier than a Ford Class aircraft carrier, and the clear favorite in any sort of collision.

In fact, the tanker reportedly suffered no significant damage in the incident that would ultimately claim one of Norway’s most advanced vessels.

Now, the Norwegian military has released footage from their explosive ordnance disposal divers that were tasked with extracting the frigate’s missile launchers:

“All diving assignments we undertake require detailed planning and thorough preparation. We must be able to solve the assignments we are given, while providing as low a risk as possible,” diving unit leader Bengt Berdal told the media.

“Our biggest concern [during this mission] is any increased movement of the vessel.”

While an investigation into the incident is still underway, preliminary reports indicate that the frigate did not heed the tanker’s warnings prior to the collision and was sailing without its automatic identification system turned on — making it more difficult for other ships in the area to locate them. You can get a better look at the damage in the video below: