OK I just wrote down by hand, the last four msgs from OP.

Here is where my thoughts lead, keep in mind, he said the key was to follow, right?

The Ch sub is blocking some sort of entrance (to what??) for Isreali Sampson class (what is that? sub? surface vessel? I forgot!).

The Cobalt is Blue sounds like a confirmation-as in, I am here do you see me? Or something along those lines. Cobalt IS blue, after all.

The TT41 is scheduling calibration....I think the notation that the translation is "extremely problematic" means that the true meaning is unknown....could simply be a state of readiness poorly translated.

Mistral MIRROR. I have been thinking about this phrase also, since it appeared. Could it be.....electronic countermeasures? Or, ECM as they are known. If conditions are perfect, there is no return signal and you're essentially invisible to certain types of "ping", correct.

Most worrisome to me are the vector ch descriptions. What is happening in the Gulf of Aden we don't know about yet? Any way to track that???