Bob, I contacted my brother regarding the work pattern when building the QE2 and he had responded as follows:
Two nights overtime ( Tuesday and Thursday) and a Sunday tended to be the norm when work was plentiful and I think that shift work was necessary when ships were nearing completion, this could have been day- night or a three shift pattern, but I have no direct experience of the shifts. Maintenance trades also worked Saturday mornings to enable them to carry out repairs etc on plant equipment.