Renown is the same, however the awards/medals are based on Type of ship sunk; total tonnage; progression of sucessful patrols; "Realism" settings in the Game Play Options. You'll get a higher award for the Type of ship you sink.....even over the amount of tonnage sunk. Two Heavy Cruisers will give you more tonnage than one Fleet Carrier.....yet, the Carrier will produce a higher award when sunk, when compared to the two Cruisers.
The Award System is terrible in the stock game. You might want to read
this 8 year old thread.