0.66%?!?

"Acting upon information received" we went for a look at theAnderton lift.
We had seen it before but, more or less, in passing and certainly not fully functional.
We hadn't time for the whole hog: River trip + Lift, but we managed a Lift up as it were. The O.i.C. boat (Does he qualify as cap'n?) gave a very interesting talk on the way down, during which he informed us that it was a lift of 50'-4" (That's 15.3416 metres).
Being amused by the odd 4" I grabbed the(virtual) calculator and reckoned the odd 4" is equal to 0.66%.
DUH?!? Who'd a thought the 4" mattered all that much with seasonal fluctuations. ;¬))
Score 1 for the Victorian engineers.