Weighty matter about the QE2
IN your report (“Pride of the Clyde”, The Herald, December 1) it is stated that the QE2 has “70,327 tonnes weight”. This is wrong.
It is true that records show the QE2 as having a gross tonnage which ranged from 65,863 to 70,327 during her seagoing career but, in maritime circles, gross tonnage is not a measure of weight. It is, rather, a measure of internal volume which originally equated 100 cubic feet to one ton. Since 1969, gross tonnage has been a pure number derived from a formula based on the logarithm of the internal volume in cubic metres.
The weight of a ship is represented by its displacement from Archimedes’ Principle : “a floating body displaces its own weight of fluid”. In the case of the QE2, the displacement during the trials of December 1968 was 49,444 tons (Imperial tons of 2240 pounds each) at a mean draught of 29ft 8ins.
At the full load draught of 32ft, the displacement would be about 54,000 tons. You can see the extent of the exaggeration of the weight, which concerns me.
For a number of historical reasons a ship’s gross tonnage, which may remain constant for many years, is well publicised and publicly available while displacement, which varies from day to day as fuel, stores, passengers and/or cargo come and go, is neither publicised nor publicly available – except for naval ships
I did not have the pleasure of sailing on the QE2 but the article did remind me of a Saturday visit to Clydebank, 50 years ago, arranged by Glasgow University Engineers Society, to see and tour the ship shortly before her departure for trials. I still remember being impressed by the depth of the pile on the carpets.
David L Smith,
4 Abercorn Road,