The best skippers are to be found on the pier, of course. But several factors seem to have compounded
- it was the return from a lengthy exercise, the the crew was anxious to get back to shore
- the captain's decision to run through the fjord under emission control (save for radio traffic)
- confirmation bias that misinterpreted the tanker's position light far too long as the lights of the oil terminal
- change of watch immediately before the collision
- abandoning ship way too soon rather than trying to fight the flooding

Simply reducing speed when they received the first warning that the might be on a collision course might already have helped to prevent disaster, rather than keeping barrelling at 30 knots with radars turned off through confined waters. Even if you dismiss the radio warnings as an error on the civilian ships' side, simply accounting for the possibility that they are right and you might be wrong would have helped a lot to keep an open mind about the situation. At least, that's my take on the whole incident.