ATT.

This is coolbert:

ATT = Anti-torpedo torpedo.

Also from MARCO POLO through Harry:

"earlier this year, the U.S. Navy was experimenting with ATT (anti-torpedo torpedo) on board USS George H.W. Bush, Nimitz-class nuclear-powered aircraft carrier. The torpedo being used was much smaller than the Russian M-15 -- they said, 6.75 inch (17.145 centimeters). I have no idea how successful the U.S. Navy was in their experiment."

Click on image to see an enlarged view.

Surface launched torpedo almost all warships now able to have an ASW [anti-submarine-warfare] capability. NOT ONLY WARSHIPS BUT ANY SAILING VESSEL PERIOD POSSESSING THE APPROPRIATE ELECTRONIC HARDWARE ABLE TO FUNCTION IN THE ASW CAPACITY!

coolbert.