fleetsubmarine,anti-submarine

美媒:印度攻击核潜艇舰队可威胁中国海上力量,但这有必要么?
严密监视!俄战舰在波罗的海跟踪北约4国海军编队
china's submarine fleet evolution
taiwan's quest to modernize its submarine fleet
us navy vs ijn fleet submarine, 1941-42