Armour plate and gun fixed to merchant ship - the sailors practice with the gun.
Full title reads: "Arms For Merchant Ships".
VS of gun for deck mounting on ship being prepared in workshop. It is loaded onto a lorry and driven away.
Various good shots of shipyard workers fixing armour plate and gun mounting to the deck of a merchant ship in dry dock, the gun is then lowered and fixed into position on the mounting.
MS Gun crew of merchant ship practising with the gun under command of naval officer.