Paragraph 7

pay to A.B. Ports the reasonable costs of such alterations to the marking and lighting of the navigational channel of the river as may be necessary during or in consequence of the construction of a tidal work;

provide and maintain on any tidal work such fog-signalling apparatus as may be reasonably required by A.B. Ports and properly operate such apparatus during periods of restricted visibility for the purpose of warning vessels of the existence of those works; and

afford to A.B. Ports such facilities as it may reasonably require for the placing and maintenance on any tidal work of signals, tide-boards, tide-gauges or other apparatus for the safety or benefit of navigation.