"BL 7.5-inch naval howitzer"@en . "yes"@en . . . . . "1917"^^ . . . . "BL 7.5-inch naval howitzer"@en . "On SS Boonah"@en . . "Bore"@en . . "The BL 7.5-inch howitzer (naval) was a British anti-submarine mortar developed during World War I."@en . "yes"@en . . "single-motion interrupted screw"@en . "TNT"@en . . . . "yes"@en . "yes"@en . . . "The BL 7.5-inch howitzer (naval) was a British anti-submarine mortar developed during World War I."@en . "HE"@en . . "Gun & breech"@en .