The BBC, Costa Concordia and the Titanic

In its recent coverage of the righting of the Concordia the BBC observes that with a Gross Tonnage of 114,000 it is twice as heavy as the Titanic. I suppose they are actually comparing the Gross Tonnage of one with the Gross Registered Tonnage of the other. These are not the same thing, but neither is a measure of weight or more properly mass or displacement. Both are related (in different ways) to the volume of the ship, and different volumes of that: GRT to internal volume and GT to volume to the skin. We may also suspect that a modern cruise ship has a substantial lightweight superstructure contributing to its enclosed volume. So on any measure related to volume two ships one similar to modern cruise ship and one similar to a 1910 ocean liner but of the same displacement the modern design should come out "larger".

From its overall dimensions and a guestimate of its block coefficient we may conclude that the displacement at design draft of the Concordia is ~50-55,000 tonnes. The published displacement of the Titanic at design draft is 52,000 tons (here we are comparing metric tons with long tons but they are close enough for my purposes).

So we see that in terms of weight (displacement or mass) the two ships are very similar.

McHugh's Fundamentals of War Gaming

In the current issue of the US Naval War College Review there is a review of McHugh's book "Fundamentals of War Gaming" on the history and theory of wargaming. This is a reprint of the third edition of 1966. The price quoted is $40, but is available for significantly less from the US Government book store. In addition a scan of the '66 edition is available from DTIC which while in places being tricky to read is free. This is particularly of interest to naval war games as it is effectively the summary of what NWC had learned about war gaming in the first half of the 20th century.

I am currently reading the DTIC download and may write more when I have finished, but right in chapter 1 we have two statements which may be taken as support for Admiral Ugaki's actions in the Combined Fleet's Midway planning games:

With reference to the conduct of manual games: "The results of interactions are evaluated by a control group in accordance with rules and functions which they are frequently permitted to override, or these decisions may be based solely on their professional judgement. New forces may be injected during the game or old ones reactivated, if, in the opinion of the director , such actions will contribute to the purpose for which the game is being played." (page 1-6)

Again on the function of the game director or controller: "He may stop play at any time, when, in his opinion, the game has served its purpose. In case of disputes and disagreements, he makes the final decision. During certain types of simulations the director has the authority to reverse or modify the assessments of umpires or the evaluations made by mechanical or electronic devices." (page 1-7)

Emphasis added by me.