T-class salvo power and paired-submarine tactics

T-class boats embodied the Royal Navy's long-range ambush doctrine, originally carrying six reloadable bow tubes and four external bow tubes for a ten-torpedo salvo. Calculations suggested that a large spread gave a high probability of hitting something in an enemy task group, including one of its larger ships. Reloading the internal tubes allowed a further six-torpedo attack. Pre-war exercises paired submarines so one could withdraw while the other fired, then return with its reload salvo. Each burst of confusion covered the next boat's withdrawal, with maximum damage and disruption taking priority over waiting to confirm kills. Where possible, the submarines could draw the enemy toward a friendly minefield whose safe passage they hoped to know.