[LukeFF]

Elanaiba posted this a while back:

Purple Heart: over 40% medium damage taken by the sub

Bronze Star: 3 ships sunk in one patrol or a DD, CL or larger combatant ship not worthy of a higher award

Silver Star: 6 ships sunk in one patrol or a CVE or CA sunk

Navy Cross: 8 ships sunk in one patrol or a BB or CV

CMOH: 6 ships sunk in the same engagement (checks for 24 h timeframe) or 2 of the following BB, CV, CVE

Also, according to the book "Wolfpack: The american submarine strategy that helped defeat Japan", the requirements/standards established in 44 by the US Navy for medals are:

Bronze Star: 2 ships sunk in a patrol

Silver Star: 3 ships sunk in a patrol or a DD or larger combatant vessel, or a special mission worthy of this award

Navy Cross: 4 ships sunk in a patrol or a BB, CV or CA or a highly dangerous mission

For all of these 2 ships damaged will be considered as one sunk.