Comparison between Traveller Rules and Modern Ship Designs

[PFVA63]

GT

If you can find a ship's Gross Tonnage (GT) which refers to the volume of all ship's enclosed spaces (from keel to funnel) measured to the outside of the hull framing you can determine it's Traveller dtons size by dividing GT by ~4.770318. Gross tonnage is a measurement of the enclosed spaces within a ship expressed in "tons" – a unit which is actually equivalent to 100 cubic feet (2.83 cu m).

Therefore the Liberty of the Seas is about 32,368.3 dtons.

Hi,

You're right about being able to use GT for estimating ship size, but I tried to stay away from GT for a couple reasons.

- 1st, GT isn't typically used for warships, so its not easy to find that type data for them

- 2nd, Sometimes for older ships its more common to find data on GRT than GT, which isn't the same thing

- 3rd, as I understand it GT isn't really a linear scale, but rather it folows a logartithmic scale where GT = V * ( 0.2 + 0.02 log (V) ), [Link] where V is the ship's total volume in cubic meters. As such a ship twice the internal volume of another ship won't necessarily be twice the GT of the other ship.

Anyway, just some additional info.

Regards

PF

 

[PFVA63]

WWI Era Ships

By dtons do you mean real-world ship gross tonnage (1 ton = 1m^3) or Traveller tonnage (1 ton = 14m^3)?

Also, I wonder if the formulae work for larger surface combatants (such as Cruisers, Battlecruisers or Battleships) and for older ships (late 19th century to early 20th century)...

Hi,

I couldn't find alot of info on the interior volume of WWI era ship's, but I did find a aimple formaul that's supposed to relate a ship's Block Coefficient to the total volume inside a ship's hull, though I don't know how accurate it is. Anyway, using that formula, and some info on a couple ships I found on the internet, I made an estimate of the total volume inside the ships' hulls, superstructures, and turrets. I've added them to the plot I put together earlier. They are shown as Purple Squares on the plot.

Anyway, based on these really rough estimates, it kind of looks like if you multiply a WWI era battleship's listed full load (hydrostatic) displacement by about 0.15 you might come up with a rough estimate of its Traveller equivalent dton size. Specifically, for HMS Lord Nelson, I came up with a Traveller size of about 2600 dtons, for HMS Dreadnought about 3200 dtons, and for HMS Bellerophon about 3400 dtons. However, I had to make alot of assumptions so the estimates are probably pretty rough.

Anyway, just thought I'd share.

Regards

PF