It must have been 1971 not 1970 when I was there. Exiting times with the 'new' technology of GRP, now called 'fibreglass'. The first trial vessels were docked at Vospers quays when I was an apprentice, at the time, in Woolston Training Center for Yacht and Boat Building, Southampton. In that year the QE II was docked there and , if I remember correctly, a nuclear submarine , I can't remember the subs name, was docked for the last time before she was sent to the knackers yard. I'll have to google the name for the sub. I was simply stunned at the sizes of these vessels, bearing in mind, I was only 17 at the time.
Strawballs, as the hulls were 'plastic' how successful were these boats? Would be very interested in your reply.