JP
What do I think?
Well I see it like this: The yachtsman appears to be familiar with Sea King helicopters, indeed to my knowledge, that is the ONLY size of helicopter he refers to.
Have you any idea of the relative sizes of Sea King and Chinook fuselages? You might be surprised at the answer!!
Cazatou
You are of course correct. Indeed it would be difficult even for experienced aviators to guess the precise speed of an aircraft.
If there were some other compelling evidence to the contrary, it would be entirely justifiable to dismiss the evidence of the yachtsman.
However, there is not!
He is the only surviving witness to the aircraft's approach to the Mull, and as was pointed out earlier, he appeared, in every respect, to be a very measured man, as far as his evidence was concerned.
Perhaps the most important thing to come out of this exchange (and I thank you for bringing our attention to it!) is that the BOI cited his evidence, and only his evidence, in support of their assertion, that the aircraft approached the Mull at high speed.
You will agree, they were wrong so to do!
This is precisely why I, and many others, continually wish to see statements of 'opinion' supported by the factual evidence upon which that opinion is based.
May I remind you:
Matters of opinion, are not matters of fact!
And contrast that with the standard of proof required here:
"Absolutely no doubt whatsoever"
Drill down to the facts, and see if you can satisfy that burden.