a colleague offered two derivations for "Not enough room to swing a cat"
1 cat-o-nine tails, you need plenty of room to wield a whip.
2 there is a ship called a cat (short for what?) and it was a yardstick for the size of a harbour, if you could not turn the ship (swing / haul) then any ship larger would have difficulty getting in or out.
so can any swinging Mudcatters crack this one? I have a feline there are more puns on the way.............