Arpeggio of Blue Steel

Arpeggio of Blue Steel is a Japanese manga series produced by Ark Performance and serialized in Shōnen Gahosha's Young King Ours. Due to global warming and rising sea levels in the early 21st century, much of Earth's landmass has been lost. In 2039, fleets of powerful sentient warships, armed with advanced technology and weaponry, mysteriously appear and devastate the world's naval forces. Gunzō Chihaya is the captain of small group of privateers called the Blue Steel. Gunzō and his crew are hired by the Japanese government to deliver the prototype for a powerful weapon, a weapon that may finally allow mankind to fight back.