Try coming in at
periscope depth, on silent running, ahead slow, no more than 2-3000 yards from the nearest escort.
I think you'll have more success.
Note: weather conditions play a big part in this.
If the sea is dead calm they can hear
real well.
In choppy seas you can get away with more speed, or be closer to the escorts.
Don't leave your periscope up for too long, they
will spot it.
Good luck
