NAVIGATIONAL AIDS
The marks and buoys are shifted as the channels change and are not to be relied 
upon; the letter against the buoys are the initial letters of the channels or 
banks to which they belongs.

DEPTHS
The changes in depths and direction of the channels are in some places very 
rapid. No one should attempt to navigate the river without local assistance.

CURRENTS
During cyclonic weather a strong westerly set of 2.5 knots is experienced.
During westerly gales an easterly set of 1-2 knots develops.