Here is a link to a story and a picture (on the second page) of one of the drydocks at Yokosuka in 1958. We were living on the bluff in Yokohama at the time and actually saw the accident happen.
The ship was barely moving when it struck the lighthouse, but it sure tore a hole in the bow. Apparently the British were able to negotiate a deal to use the Yokosuka facility for a repair.
RMS Caronia Timeline: Accident at Yokohama 1958 - Page 1 - The Accident Described