Well, anywhere you hit a sub with a penetrating hit is a very bad thing. If the saddle tanks get ruptured, the sub cannot surface. If the internal hull is breached, you drown rather than suffocate. As for the small size of the torpedo, this allows them to be carried by a wide array of aircraft and surface ships. Of course, I am just guess that these were ASW designs. This is way out of my area.
George
About TDS
I suppose ASW applications can't be ruled out. However during WWII the US Navy was conducting trials with HCR2 armor added to ship models. HCR2 is a "plastic armor" (the actual constituents comprise aggregate and pitch-mastic binder -- sort of akin to Asphalt Concrete -- but with a lighter unit weight). HCR2 basically acts to erode a shaped charge jet. The HCR2 testing program was eventually abandoned. But the fact it existed at all suggest that the concern over shaped charge torpedoes may not have been limited to submarines.
One additional bit regarding the Shaped Charge Torpedo Bandwagon: According to an Ordnance Intelligence Report Number 11 (OTIR No.11, Office of the Chief of Ordnance Officer GHQ, AFPAC, Tokyo, Japan, ca 1946) the Japanese developed both 18-inch and 21-inch torpedoes that employed shaped charge warheads. Both used 45-degree conical liners -- the liners were steel. No idea regarding either of their application – ASW or Ships?
One additional bit regarding the Shaped Charge Torpedo Bandwagon: According to an Ordnance Intelligence Report Number 11 (OTIR No.11, Office of the Chief of Ordnance Officer GHQ, AFPAC, Tokyo, Japan, ca 1946) the Japanese developed both 18-inch and 21-inch torpedoes that employed shaped charge warheads. Both used 45-degree conical liners -- the liners were steel. No idea regarding either of their application – ASW or Ships?