I checked their HE damage damage for their TB torps and bombs (only for T2 but i guess it's consistent with T1)
Their TB torp damage is between RN and USN making thme second best.
Their DB damage is somewhat low placing them between RN and USN as well.
On top of that their bombs seem to be one of the lightest in the game standing at 640 while SN bombs are 750 meaning they will do even less damage when dropped from max alt compared to SN.
Only RN has lighter bombs (625 ).