And for London's super rich, the River Thames will be an uncluttered highway to zip from party to party, from event to event in a flotilla of speedy yet breathtakingly expensive boats.

The yachts are a boon to the Canal & River Trust, the charity that runs West India Dock, which fell into decline in the 1960s and closed in 1980s before a revival in the 1990s.

Superyachts equipped with helipads and submarines have joined Britain’s biggest warship, more than a dozen tall ships and cruise liners on the Thames River for the Olympic Games. Octopus, the yacht ...