Pontius Navigator wrote: ↑Sat Jan 08, 2022 8:50 am
The array is less sensitive in the ahead or astern sectors and the warship was manoeuvring to change aspect (pure guess)
The array is extremely accurate in detecting and measuring the very precise distance, and therefore the cumulative relative bearings, of the emanating target from the array. It does so by measuring the phase differences of the arrival times of the sound wavefront at each one of the known positions of something like 1,024 hydrophones along a mile or two, whose positions are known accurately from the ship's track.
What it can't do, without additional data, is determine which side of the baseline, ie the eel, the target is on.
Sub skippers know that. They know how to play games such as maintaining the same distance from the nearest part of the array and ducking and diving under the array and coming up on the other side. The array itself can't discriminate that.
The frigate drivers know that too, so they alter course so as to check that the target is still on the side of the baseline that they thought it was.
The sub appears to me to have deliberately made its presence on the Stbd side quite conspicuous by popping up to display its search periscope and its comms mast within plain sight of a helo and perhaps from the frigate herself in broad daylight. Submarines tend not to display their presence on the surface without good reason. Russians are bloody good at chess while Pusser plays Uckers (Ludo).
I do wonder whether such subsequently submerged manoeuvrings played a part in this collision.
Of course, we'll never know.
The official script of the 'embedded' ones reads that the pesky Russky sub collided with Pusser's sonar, not the other way around, nor any combination thereof.
So that's that, then.