Below is the list of the series of Type91 aerial torpedo production models. Germany approached Japan requesting the transfer of Japanese aerial torpedo technology. They also supplied the Germans with blueprints of the Type 91 aerial torpedo. She was later finished off by an aerial torpedo. On 23 November she was struck by an aerial torpedo. She was hit by several bombs then by an aerial torpedo. He considered the Type91 aerial torpedo to be his great achievement. The Type 91 aerial torpedo had two unique characteristics. A proper aerial torpedo could have prevented such losses. The GT-1's warload consisted of a Mark 13 Mod 2A aerial torpedo. "Noshiro" was hit by a dud Mark 13 aerial torpedo. After World War II, anti-aircraft defenses were sufficiently improved to render aerial torpedo attacks suicidal. The aerial torpedo could not even be released at speeds above . An Italian torpedo bomber hit "Nelson" with an aerial torpedo and reduced her speed. The Type 91 was an aerial torpedo of the Imperial Japanese Navy.