OK,
I will put my head above the parapet.
When giving evidence to the BOI the yachtsman, Mr Holbrook (the lone yachtsman), stated on oath to the RAF BOI that the Chinook was travelling "somewhat faster than Sea Kings in level flight" and that the visibility at sea level was "about one mile limited by haze". MOD state that a Sea King in transit will typically fly at an airspeed of 100-110 kts.
At the FAI he estimated the speed of the aircraft to be 60-80 knots. He also indicated to the FAI that he watched the helicopter for some 25-30 seconds, during which time he was manoeuvering his yacht around fishing boats (although in evidence to the BOI and the HOL Committee he indicated that his sighting of the aircraft was limited to a 5 second view.)
I used the phrase "the lone yachtsman" because that is how he was described by the BOI who were, no doubt, thankful that they had at least one witness to the last minutes of the fateful flight. However, at the FAI he stated that he was manoeuvering his yacht around fishing boats and watched the helicopter for only some 25-30 seconds.
Let us unpack this:-
The "Lone Yachtsman" of the BOI is surrounded by "Fishing Boats" who, of course, have a crew. We have no idea of the size of these boats, but if it was only someone to steer and someone to gather the fish then that is 2 per vessel. If it was only 2 vessels then that is 4 witnesses. However he never mentioned the boats to the BOI.
Then we come to the HOL Committee.
This is his "Piece de Resistance" where he suddenly unveils to the Committee that he called down to his "Cabin Boy" "to come and look at the helicopter that is coming to rescue us""
Cabin Boy???
He never mentioned this to the BOI either
So; if there were only 2 "Fishing vessels" with a 2 man crew apiece then; then,with the addition of the "Cabin Boy," there were a total of 5 "Witnesses" who were never interviewed by the BOI because they were unaware of their existance.
One final point. He was the "lone yachtsman" - except we now know that he was not alone. How many other potential witnessses were there whose evidence was never heard because "The Lone Yachtsman" got in first and neglected to mentiom their prescence to the appropriate authorities at the time?