I debated about putting this in the "How big is the
Enterprise" thread, but since the ship in question isn't the E, I figured I'd best put it here.
Remember the debris field in Vulcan's orbit -- especially that large saucer section?
Of course you do
I stumbled across an image of the E headed toward that saucer. Regrettably, I've yet to see an image of
Enterprise ducking "under" the derelict, which would undoubtably be superior for scaling purposes.
Anyhow, I thought I'd still give it a try.
Since the E's own saucer width isn't fully evident in the image, I figured I'd scale according to the size of her shuttlebay:
Given the perspective, it's clear the shuttlebay's width is, in reality, substantially less than 15% the saucer's diameter.
However ...
... since we see the ship from behind and the object we're scaling is farther from the camera, that's unimportant; all that matters is the apparent, or relative, sizes.
As you can see, the derelict saucer's projected diameter is approximately the same as the
Enterprise's (and over 6.7 times the shuttlebay's width -- 6.8, to be exact).
These are fairly rough measurements, but I think they irrefutably demonstrate that the destroyed saucer is significantly larger than
Enterprise's own.