Aidan Stanger wrote:
Paul Terry wrote:
Tom Anderson writes

Play fair - the boats have rather lower capital costs than the
tubes, since the track's already there.

On the other hand, the "stations" have to go up and down with the
tide

Anyone who has been to Venice will know that efficient water-borne
transport is possible (although it is massively subsidised), but
the tiny tidal variance in the lagoon allows for very lightweight
landing stations and very fast and efficient two-crew operation
(probably taking no longer than a tube stop).

The great rise and fall of the Thames necessitates complex pontoon
structures, and I suspect that the UK's HSE would not approve of
ACTV Venice's operating procedures that facilitate three-minute
service intervals and timings of one minute per stop.

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.
--
Richard J.
(to e-mail me, swap uk and yon in address)