All it tells you is how much empty space is inside of the ships. It doesn't even account for all the volume taken up by the actual structure of the ship, and this all makes it quite useless for measuring warships in any meaningful way.RThurmont wrote: If you've got a better metric, then please, share it with us. GRT output per annum indicates exactly how much "ship" can be produced in a given year,
Except such a comparison would only work if an ISD and SSD have the same ratio of internal empty volume to structure and all other things, which is rather unlikely. And a single larger freighter could easily have a dozen times the GRT of an ISD, while requiring far less resources to build.
irrespective of how many actual ships were commissioned, and the increased percentage of resources building large ships were required. So for instance, KDY could be building 5,000 ISDs per year, then start building 100 SSDs and 4,000 ISDs per year, with out a big change in GRT per annum, since obviously the SSD is much larger (those figures aren't exact, just to give you a sense of the advantage of measuring output this way).
The recently completed Queen Elizabeth II is over 150,000 GRT, but actually displaces only about 85,000 tons, and she cost only about 800 million dollars, less then the price of a 9000 ton Arleigh Burke destroyer. This is a demonstration of how useless GRT is for measuring building capability. About its only use in real life is as a means of calculating tolls for canals and docking, virtually its only reason for existing.
