boom

I went out on the timber boom and made a few casts, but with little success.

The wooden upright was now standing in the middle of the floor, and the two booms were fitted into its grooved side and hoisted as high as hands could reach. … Two by two, one at each end, the students proceeded along the boom, hanging by their hands, monkey-wise. … Two by two the students somersaulted upwards on to the high boom, turned to a sitting position sideways, and then slowly stood up on the narrow ledge.