Blue Submarine No.6 (English)

After surviving another undersea battle with Zorndyke's forces, the crew of Blue Submarine No.6 returns to base for some repairs.

As Tetsu drifts in the open sea, he becomes unconscious. As he comes to, he finds himself on the hull of a half-sunken ship.

The Blue Fleet goes to Antarctica to take on Zorndyke's forces. It's a grim solution that no one wants to use, but there are no options left.