sentences:  The "Algerine" class was armed with a QF Mk V anti-aircraft gun and four twin-gun mounts for Oerlikon 20 mm cannon.The latter guns were in short supply when the first ships were being completed and they often got a proportion of single mounts.By 1944, single-barrel Bofors 40 mm mounts began replacing the twin 20 mm mounts on a one for one basis.