Weather was Hazy; visibility 6 - 8 miles, ceiling unlimited; wind SE, 8 knots. The aircraft was a J4F-1 amphibian and the enemy was believed to be an Axis submarine of the 740 ton class. The attack was a gliding beam attack with one MX XVII, Mod I depth charge and the enemy crash-dived.

BRIEF DESCRIPTION

"Covering rear of convoy, sighted submarine surfaced and trailing convoy. My altitude was 2,000 feet and about four (4) miles away. Headed for submarine and released bomb at about 500 feet on course 170 degrees True."

STATEMENT OF PILOT (Marvin W. Thompson)

"I was escorting a group of vessels in convoy on July 31, 1942 enroute to Southwest Pass. While covering the area astern of the convoy, my radioman sighted a long wake to the southwest of our position at about four (4) miles distance. I was at 2,000 feet heading west. I changed course and headed towards the wake losing altitude. I felt fairly certain that this was a submarine as I had just covered that area a short time before. As I neared the position, the submarine came into view through the haze and was in an easterly course parallel to the convoy.

I then was at doubt whether there was time enough to permit an approach from astern and perhaps offer the submarine a chance to submerge and escape or to make a direct attack from my present position. At the time I was in a shallow dive losing altitude. I then decided to attack at once (Someone penciled in 'Thank God!' at this point on the report) and headed for the submarine's beam in a 35 degree dive or glide with an air speed of about 130 knots. After estimating the point of release I dropped the bomb and pulled out of the dive over the submarine; made a climbing turn to the left and came around and observed the explosion had been from 300 to 500 feet short. At this time the submarine was almost completely under the water having made a very fast crash dive.

I remained in the area dropping smoke bombs at intervals to mark the area. I tried to communicate with the convoy' escort vessels but did not succeed due to interference, however, one of the SC boats was seen heading toward the position of the attack, so apparently they had received the information. Another J4F-1 plane arrived and after indicating the position to him I returned to Houma, Louisiana since I was low on gas.

I realize now that I should have made a gradual spiral to a point astern of the submarine in an attempt to make an astern low altitude attack, keeping the submarine in view and as soon as he started to submerge head directly in on a low altitude attack. (someone penciled 'NO!' in the margin of the report at this point).

More U-166

U-166 Profile and History
Official US Coast Guard Reports of the Action: Introduction
US Coast Guard Report: July 31, 1942
US Coast Guard Report: August 1, 1942
Report: July 24, 1942 Sinking of the SS Oneida
Report: August 5, 1942 Sinking of the SS Oneida
Report: Summary of Statements from M/S Gertrude Survivors
Report: August 13, 1942 Sinking of the SS Robert E. Lee