“While coastal forces are the most suitable forces to operate in mined areas, the enemy has so strengthened his escorts and armed his shipping that our coastal craft find themselves up against considerably heavier metal. Furthermore, the enemy’s use of F-lighters of shallow draft does not provide good torpedo targets. Everything that can be done to improve our chances of successful attack is being done. Torpedoes will, if possible, be fired at even shallower settings. Meanwhile, if they cannot achieve destruction, coastal forces will harry the enemy and endeavour to cause him the utmost possible alarm, damage, and casualties.”
Officers at La Maddalena gave longer thought to the problem and came up with an idea called Operation Gun.
Lieut. Commander Barnes’ combined operation—the plan to use American radar for scouting and conning heavier-armed British boats to targets—had been a promising beginning, but even the MBG gunboats were not a real match for the F-lighters.
Commander Robert A. Allan, British Commandant of the Sardinia base, cut three landing craft out of the British amphibious fleet and armed them with 4.7 naval guns and 40-mm. autocannon. The landing craft were big, flat-bottomed tubs, wonderful platforms for the hard-hitting 4.7 inchers. To man the guns, he assigned crack gunners of the Royal Marine Artillery.
Commander Allan organized an interesting task force around the three landing-craft gunboats (designated LCGs) as his main battle line. They were screened against E-boat attack by British torpedo boats, and controlled by the radar-equipped American PT scouting force.
Commander Allan himself went out on the first sweep of his beefed-up inshore patrol on the night of March 27th. He rode Lieut. (jg) Thaddeus Grundy’s PT 218, so that he could use American radar to assign targets to his gunboats and give them opening salvo ranges and bearings by remote control.
When the gunboat battle line arrived off San Vicenzo, south of Leghorn, a scouting group of two PTs, under Lieut. Dubose, went off on a fast sweep, looking for targets. At 10 P.M. the PTs had found six F-lighters going south, and Commander Allan brought his main battle force up quickly to intercept them.
At 11 P.M. Lieut. Dubose sharply warned the main force that two destroyers were escorting the lighters on the seaward side. “I am preparing to attack the destroyers,” he added.
Commander Allan continues the story: “Until he carried out this attack, it was not possible for us to engage the convoy, as our starshells being fired inshore over the target [to illuminate the F-lighters for the gunboats] would illuminate us for the escorting destroyers which were even farther to seaward than we were. Fire was therefore withheld during several anxious minutes.”
During this ten-minute wait for the PT scouts to take on the destroyers, both the German forces, escort and convoy, came on Commander Allan’s radar screen.