When I lived overseas I used to be "ferried" across the harbor to get
to school. The boat was a former lifeboat with an engine inboard,
a visible propeller shaft, and a screw in the water to push it along.
Large tiller to steer it. We kids used to get to take the tiller
occasionally.

A ferry we took across a river outside town, now and then, was made out of water tanks welded together. The deck where the car (usually only
one) sat, was made out of airstrip steel decking. There was no
motor. Getting across the river meant pulling on a cable. It must
have been attached to pulleys on the bank but I am not sure since
I forgot to look, or ask, how that worked.

My brother and I liked to pull on the cable to move the ferry across the
water. I don't know if I'd get the same kick out of it now.