Some crazy thoughts
 

As many of you know, one of the biggest problems with dodging a torp in a sub is when the sub goes flank it also loses the sight of the torp on the sonar screen. Has anyone thought about loading some sonobuoys onto the sub and connecting them with the mother sub with datalink (just like between air plaforms and their sonobuoys). When the sub starts going too fast to track the incoming torp, the buoys can track them and pass info back to the sub. So, the sub can travel at flank while accurately tracking torp at the same time.

Submarine's active intercept receiver can work at flank speed I think. But there really is no way to connect a submarine to a sonobuoy while going at that speed. Eventually the buoy would be dragged by the sub like a towed array if they use a physical connection, and acoustic links are a very new technology and could be jammed.

The data link between a sonobuoy and an aircraft use radio frequencies (Presumably VHF or EHF), which do not transmit well, if at all, through water. So it's not an option.

so there is such a thing called accoustic link underwater?

Yea it basically uses an Underwater Telephone to transmit data back and forth. This is going to be used on the new UUVs the USN is developing but it has yet to be in a deployed weapon system.

Beside, one assumes that if the sub can't hear a torpedo (Loud, high frequency), it won't be able to hear a data link (Presumably not as loud, high frequency)

well, I am assuming datalink would function like something similar to active intercept. That's the only things works at high speed.