In message , Richard J.
writes

Thames Clippers run a service from Savoy Pier to Woolwich Arsenal.
Savoy Pier is quite close to Embankment Tube station, 3 stops south of
Tottenham Court Road on the Northern Line. River service details are
at http://www.tfl.gov.uk/river/timetables.shtml, though you would need
to check nearer the time of your visit after the summer schedules are
piblished.

Its worth noting that few if any boats run right through from Savoy to
Woolwich in the winter timetable - a change is usually needed at Canary
Wharf. Also, boats to and from Woolwich only run during the rush hours
(plus a few mid-day services on Saturdays). The summer schedule may well
be better, although I think the extension to Woolwich is somewhat new
and experimental.

To travel by river, it might be better to go to Greenwich from central
London - there are a number of reasonably frequent services, including
one from right outside Embankment station. Its only a short walk from
Greenwich pier to the 177/180 bus stop for Woolwich.

Otherwise, take the Northern line from Tottenham Court Road to Waterloo
- follow the signs for Waterloo East station and, as you say, take the
train from there directly to Woolwich Arsenal.

--
Paul Terry