I've taken down plenty of shore batteries with it.
"The installation of larger-bore cannons culminated in the fitting of the 40 mm Bofors gun[18] on the aft deck. Starting in mid-1943, the installation of this gun had an immediate positive effect on the firepower available from a PT boat. The Bofors cannon had a firing rate of 120 rounds per minute (using 4-round clips) and had a range of 5,420 yards (4,960 m)."