On 21 Apr 2016 at 21:45, Richard Aiken wrote:

> Going by the displacement given for the cruisers (75,000 dtons) and
> the RL historical precedent that battleships are generally twice the
> mass of cruisers, the displacement of the Fair Phyllis *should* be
> 150,000 dtons. 

I'd say x3 is a more common ratio. Dreadnoughts (and battlecruisers) were roughly
25KTons (smaller if pre-WWI USN ships, because congress wouldn't pay for bigger).
Cruisers were ~7KTons, and not yet at the 10Kton mark.

Treaty battleships were capped at 35KTons, and cruisers at 10KTons. By WWII when
cruisers had grown to 15-16KTons, battleships were in the 45KTon+ range.

BTW, destroyers were about 1/5th to 1/3rd the displacement of cruisers, giving a
pleasing x3/step increase (very pleasing if you happen to use GURPS Spaceships for
your ship design work).