Free! - 岩鳶桜の咲くころ

Pairing: Makoto x Haru

From Seabreeze Romance Scanlations:

It is the Taisho period. Haru is a painter, and his childhood friend Makoto is an enlisted soldier. The tranquil peace they have long enjoyed is broken when Makoto is deployed to fight on a naval carrier. The prospects seem grim, and Haru finds it hard to keep hope. Will Makoto make it back alive, or is Haru destined to paint the sea alone?