Reaction ferry

Some reaction ferries operate using an overhead cable suspended from towers anchored on either bank of the river at right angles to the current flow.

Ferries without a rudder change the relative lengths of the bridle or multiple tethers in order to steer.

A now rare type of reaction ferry uses a submerged cable lying on the bottom across a river or tidal water.

It passes through moveable pulleys or belaying points whose location sets the ferry's angle.

In order to set off, manual work is required to initially pull the cable and also to manoeuvre, especially during the turning of the tide.

A reaction ferry operates as a sailing craft where the traveller pulleys represent the wheels of a land yacht and the moving fluid is the water current rather than the wind.

For the anchored-tether type ferry this is valid when the tether is parallel to the current, near the middle of crossing.

[2] For reaction ferries, L/D ratios also apply except that one is very high, for example typically 30 for a traveller on a steel rope, as visible in aerial photographs, and the other can vary from low, e.g. 1-2 without a centerboard, to 3.5 with one.

The amount of lift required is set by the angle of incidence of the ferry to the apparent current (here 10°), often done with a rudder (not shown).

Several reaction ferries crossed rivers in the Ozark Mountains of the central United States during the first half of the 20th century.