We have encountered three,torped two,& deck gunned the other. set depth to shallow,fast,or slow,depending on range. if undetected,set PK to track,if his course is constant/unchanging.other wise dive to 62ft,& track with sonar,when she comes in-range,blow,deck gun,with HE,took five good shots. You could head for thermal. cover.

BTW,we encountered our first Jap Sub on the surface,she dove,we had set PK,fired at 50 depth,& got a torp impact! splash,Amazing,no confirmed kill.

No it wasn't a circle runner.