There is very little traffic on this fine lake [Lower Lough Erne]; the only boats upon it, called cotts, are, like our coal-barges on the Thames, square at each end, flat-bottomed, drawing little water, and rigged with one large gaff-sail; and seldom exceed the burden of ten or twelve tons.
The natives who manage them are miserable sailors, who, with the least breeze that blows, may be seen skulking under the lee of one of the islands. Their chief employment is carrying turf from one of the bogs near the shores of the lake to Enniskillen, stones and sand for building, and slates and coal from Beleek, which have been imported at Ballyshannon.
John Barrow A Tour round Ireland, through the sea-coast counties, in the autumn of 1835 John Murray, London 1836
Irish waterways history 