a)      the determination of the location of markers, buoys, beacons and leads for the use of shipping approaching a declared port or in bays, rivers and estuaries used by shipping; and

b)      in bays, rivers and estuaries used by shipping –

        (i)      the dredging and deepening of channels; and

        (ii)    the determination of the location of berthing and mooring places with or without wharves or jetties ; and

the investigations, rivers and estuaries with a view to ascertaining their suitability for use as ports or by shipping