Ingame, a ship equipped with both a Sonar and Depth Charge will have a 15% damage boost against enemy submarines.This bonus only applies once per ship (i.e A second pair of Sonar/Depth Charge equipped on the same ship will NOT gain another 15% boost) Equipping a Seaplane Tender with a Depth Charge along with a Seaplane Bomber will increase damage against subs. * Green : Outstanding * Yellow : Above average