On Friday 24th June 1966 Cardiff Queen was in drydock at Cardiff after a leak had been found in one of her bottom plates the previous morning. This is something which happens from time to time in the hulls of ships as they grow older particularly in those of riveted construction as it is can be caused by corrosion around a leaky rivet or in some cases by a rivet having fallen out after its head has completely rusted away.
One technique to fix it is to pop a cork attached to a piece of string out through the hole, catch it when it floats to the surface around the ship's side and then attach a bolt of suitable size to the string and draw it back underwater and up through the hole to temporarily plug the leak.
Another technique is to fit a cement box and this is what was done to Cardiff Queen on the Thursday morning in the presence of a Board of Trade surveyor. Cement boxes are not rocket science. They are just what they say they are. You make up a wooden box around the leak, pour concrete into it and wait until it sets. Hey presto, the leak stops.
Like the bolt on a piece of string, cement boxes are not a permanent solution but they get you through for the time being. It wasn't a common occurrence but it did happen. I remember that we had to fit one to Waverley's bottom in the boiler room when she was in the Solent at a time when I was aboard providing my services as pilot for Portsmouth Harbour in 1997.
Cardiff Queen's cement box enabled her to undertake a charter on the Thursday evening from Swansea. She then sailed to Cardiff to be dry-docked for a proper repair on Friday 24th June and was back in service from Cardiff at the weekend.