While pootling along the river in a pleasure cruiser can be a relaxing way to soak up the sights, those who like their sights with a side portion of adrenaline are best off hopping aboard a 12-seater RIB from Thames Rockets. RIB being, of course, Rigid Inflatable Boat, these sightseeing tours in London get you very close to Thames Water indeed, in a very fast (30 knots/hr) 12-seater dinghy, travelling from the London Eye, and visiting all the riverside sights from the Houses of Parliament, out past Greenwich to the Thames Barrier (there are two tours, 50 and 80 mins).Thames Rockets also run the VIP O2 enclosed RIB shuttle that does O2 transfers from anywhere along the river, 24 hours a day, for £425/hr. Also available for private charter.