An even shallower climb gradient was displayed by the cargo DC-4's and DC-6's headed southward out of MIA. They would take a turn to miss buildings on the beach and gradually struggle to an initial altitude over the water.
Was there not the case some years ago of such a 'prop cargo plane' losing thrust on 1 engine after takeoff and not being able to climb, so they dumped it in the sea just off the beach. I read they were in the dinghy and on the sand before the services arrived to see the fin sticking out of the water and the a/c resting on the bottom.
Long before Sully.