The new channels were named after William Craighill, a lighthouse board member who supervised the surveys for the excavation.

For the rear light a grid of nine stone piers was laid out, and a pyramidal iron tower was erected.

A central shaft of wood timbers sheathed in iron plates held the staircase to the lantern, and a wooden house surrounded this at the base of the light.

The expense of constructing foundation for the two lights exhausted the original appropriation and delayed completion until 1875; in the intervening two years lightships were used instead.

The wooden construction of the central shaft had problems with rotting almost from the start, and as recently as 1994 a Coast Guard study suggested that it be removed.