B26s carried and dropped torpedoes at Midway but got no hits. I don't whether the aerial torps suffered with the same maladies as the larger ones but they were slow and had to be dropped low and slow and were not very effective. I wonder if the torps carried by the B26s were carried internally or externally.
They also flew a few missions with them later in 1942 in the Aleutians, again without definite success. Then, B-26's in the Aleutians obtained at least one significant sinking with skip bombing.
There was nothing basically wrong with the Mark 13, but it had the same kind of flaws as the other major US torpedo models of the 1930's (Mark 14 sub, Mark 15 DD). Not the same exact flaws, but same pattern of relatively minor issues that hadn't been debugged properly, because of lack of sufficiently realistic testing and general dysfunctionality of the Torpedo Station at Newport, the main design agent. While realtively easy to overcome once isolated, these flaws caused a lot of failures in the meantime. And the Mark 13 originally had quite restrictive launch criteria in height and speed, often naturally exceeded in combat operations. The re-engineered versions had much wider launch envelope, and again this didn't involve a fundamental re-design, just detail work on various components, plus the ring tail and break-away plywood head. In Mark 13's case the rework was done by Cal Tech. It's true the improved torpedoes were only issued in 1944, when they proved reliable and had as wide or wider speed/altitude envelope as anybody else's aerial torps.
But again, the USAAF wasn't mainly looking to launch torpedoes and foiled by the Mark 13. They were looking for an alternative to medium altitude bombing of ships which the USAAF *gradually* agknowledged was not getting a lot of hits*. Skip bombing was one idea and it proved spectacularly successful, no reason to look back at that point. It was not just against '500 ton luggers. Skip bombing was deadly v. full size (in those days several 1,000 ton) merchant ships, escorts, and DD's and severly damaged cruisers in a few cases too.
*in air-air case we still sometimes only have one side's account so it's still often quoted. Whereas actual sinkings of Japanese warships and large merchant ships, were mainly (with some later corrections) catalogued by the late '40's. But in say 1942, the USAAF was still going partly on its own claims of far greater numbers of Japanese ships sunk, eg. sinkings by B-17's at Midway which didn't occur; but was gradually realizing the hit rate was too low.
B-26 in the Aleutians w/ underslung Mark 13
Joe