This movie, which i revisited on German and English DVD yesterday is definitely more in the B Movie of the Sub Marine Genre. They could have learned from watching Destination Tokyo more closely, as this was with all its limitations still a fine movie and much less a strange flag waver whilst closer to the actual war time. Ward Bond and John Wayne still look like somebody stole their horses and don't know where to go, the submarine is spacious as an Ikea show room and the stress level when depth charged more like a tenant being annoyed with next door noise when watching Super Bowl. What did work quite good was the Wayne - Neal relationship, which you will see much more developed and mature in Harm's Way about 20 years later. Not urgent to watch.
Review of Operation Pacific
