Russian Sub Surfaces Nearly 3 Days Later

"Officials said the Russian submarine was participating in a combat training exercise and got snarled on an underwater antenna assembly that is part of a coastal monitoring system. The system is anchored with a weight of about 66 tons, according to news reports." My Way

You know I have to admit that this sub story is the first I ever hear of these "underwater antenna assembly "s.
Does anyone know what they are talking about?