Richard J. wrote:
Aidan Stanger wrote:

Actually operating boat services on tidal rivers is very easy! The
(small) CityCat on the Brisbane river, and (large) Sydney ferries
on the Paramatta River do it all the time.

But IIRC the tidal rise and fall in Sydney is quite small. In London
it can be more than 7 metres.

Apart from the obvious need to put in place piers with sufficient rise and
fall to allow a comfortable transition between vessel and terra firma plus
vessels with sufficient power to work against the tide, how does that make
any significant difference?