Cabin Sizes

Long time enjoyer of the books and I've got my head around nearly all the nautical elements in a remarkably un-lubberly fashion.

I am however not particularly good at judging the size and scale of various aspects of shipboard life, however many times a midshipman patiently explains the length of the barky.

The tiny cabins afforded to officers, other than the captain's comparatively luxurious quarters, are the trickiest thing to get a proper sense of for me. Anyone got either a decent illustration or modern comparison so that I can finally fix in my mind how little space Stephen had to swing a metaphorical cat?