Archive for July 20th, 2011

The capstan

20 July 2011

Contributed by Brian J. Goggin

A capstan is used for winding in a rope with a large load on the end. It has a vertical axle, allowing many people to throw their weight on the bars.

There is a capstan just upstream of the bridge crossing the Shannon at O’Briensbridge in Co Clare. From the late eighteenth century until Ardnacrusha power station was built in the 1920s, the Limerick Navigation ran under the bridge, linking the Shannon Estuary to Lough Derg. There was a three-knot current through the bridge, very difficult for boats (which were poled, rowed or sailed) to get through. Horses could not help because the navigation arch, the one that boats had to go through, was the fourth out from the bank.

That was why a capstan was installed. A rope was floated down through the navigation arch; boats coming upstream secured the rope and were hauled through the arch.

This makeshift arrangement, and other deficiencies in the navigation, did not matter very much at first. Like most Irish waterways, the navigation carried little traffic: perhaps only ten small boats were using it in 1800, carrying low-value cargoes (turf, sand, lime, stone, dung) as well as more valuable slates and corn downstream, coal and timber upstream. Read More