Originally Posted by willk
I dunno. Imagine that your engine had broken down in a dangerous place. How fast could a large vessel in the vicinity stop to rescue you?
An uninterrupted run across the entrance takes the chain ferry about 3 minutes.
With a distance of approx 250 yards to travel this gives the ferry a speed
of approx 83 metres a minute.
Slowing down from just over a metre a second in a 125 tonne ferry....
I bet there are some commercial skippers on here who could give you that answer.