How many torpedoes would be fired at a target?

This would depend on what type of ship the target was. Generally, the larger the ship, the more torpedoes that would have been used. The more armored the ship, the more torpedoes that would have been needed. If the target was pointed right at the boat, such as a destroyer or other escort, the captain would likely only fire one at a time if he dared the shot at all.

Carriers and battleships rated all six torpedoes if firing from the forward torpedo room or all four from the after torpedo room. Destroyers might rate two or three. Cruisers and large cargo ships and tankers might rate three or four. Smaller cargo ships might rate only two.