A mysterious object attacks and destroys any ship or submarine. Submarine 707 has the mission to search for that mysterious object, when summoned by a whale to follow it. The whale leads them to the world of Mu. But on their way they meet the mysterious object. They find out , it is Commander Red Silver, who had attacked the world of Mu to get Mu's magma sources. Submarine takes up the battle to defeat Red Silver and save Mu, and the world for that matter.
*Note: This review is prior to watching the "prequel" OVA series Submarine 707R that aired 6 years after this OVA. This may or may not be subject to updating after watching the 707R OVA series.*
Successful anime are often contingent on a variety of factors, notably how well it is adapted from the original source, the quality of the storytelling, the art, relatable characters, and in some cases the popularity of the manga beforehand. When it comes time to adapt an anime, studios will either approve a full-blown series, a short series (generally OVA/ONA format), or a one-shot (a film or pilot episode depending on the
studio and material being adapted). Unfortunately, Submarine 707 falls into the third category as an example of how to fail to adapt a story.
The original manga, created by Blue Submarine No. 6 mangaka Satoru Ozawa, was unique for its time during the mid-60s at the start of the rise in anime and manga. Submarine warfare, involving intricate plot lines with sonar technology, homing torpedoes, and general naval combat with a "mecha" feel allowed its popularity to grow and set the foundation for future works by Ozawa. There was an initial attempt to make an adaptation but it fell short in production. Three decades later in 1997 we were treated to this adaptation. Where this OVA "pilot" fails is a result of its brevity forcing the hand of the staff. Whether this is the blame of the studio, the director, or a combination of multiple factors does not change the fact that this contributes to the majority of the drawbacks in the final production. This leaves us with an at best average OVA that had the potential to be more.
The story is thrown in medias res, with a shared commonality to poor pilots of the era with a rushed introduction to the dilemma before the introduction of the main characters. Thereafter, the OVA swiftly goes between a few short battles, a brief dialogue between the villain and one of the characters, and finally the concluding battle. This is also not to mention the story suffers from a subplot that is introduced and then hinted once more at the end yet is never fully realized, especially considering its implications on the main story. Furthermore, the mechanics of submarine warfare are drastically simplified, and while some maneuvers of naval warfare are present, they aren't fully realized and nearly rely on the enemy falling for "convenience" or being too incompetent as to fall for simple traps.
To its credit, the art and animation quality are relatively acceptable with smooth transitions between frames and nice character designs. The Seiyuu performance is done nicely. Overall, if you're looking for a quick 45 min watch and can look past the clear plot holes and shortcomings for an average sitting, then this anime should fit well in that regard.