I was trying to make the point that your theory rests partially on the 30 knot target being a submarine, when there is no docmentary evidence to support that assertion. I don't know what the 30 knot target was, but it was just as likely a helicopter or a surface vessel as it was a submarine.
Absent the submarine or any military platform, your theory is inoperative. There being no evidence of either, your foundation is nothing more than the ground floor of a house of cards.
Surface vessels do not leave a propeller wake. They leave a bow wake. Their propellers are under water. A modern sub with a stealth design prop has a portion of the prop above the water when running at or near the surface. Any flying craft does not leave any wake in the water, other than a sea plane which is not flying in the normal sense if it is in contact with the water. The witness stated that the wake was like foam which, to me, is an asymmetrical shape off to one dominant side. What other than a modern sub would do this? And why did you give an exact type of helicopter if you don't know?