 The engineer for the whole line was William Jessop, and the resident engineer was Thomas Hollis, and he was probably allowed considerable autonomy by Jessop.The stonemason was probably John Simpson, who had been extensively employed by Jessop at Ardrossan and on the Caledonian Canal.Hollis was refused permission to dismantle part of the mill dam to lower water level for pier construction, and "in July 1809 he was authorized to proceed by means of a cofferdam, involving 'very little more expense', with the advantage that 'the stones for the bridge can be floated down on a punt'."