Mr Knapp says more canals must be built to accommodate the bikes
The Monster Raving Loony Party in London has launched its manifesto - calling for floating bicycles to ease the city's transport problems.
Knigel Knapp, parliamentary candidate for Hackney North and Stoke Newington, said people could then cycle on canals.
A Labour spokesman said the Conservatives may be the "real Loonies" while the Liberal Democrats said only they would protect public transport.
The Tories said a Labour win would mean years of "grim" travel in London.
Mr Knapp, who calls himself shadow minister for big fibs and blatant lies, demonstrated the "Loony Bike" on the River Thames near Parliament on Sunday.
He said: "What with global warming everyone might have to use them when the sea levels rise.
"In the meantime we might have to build a few more canals and that can only be good for the unemployment figures."
But a Labour spokesman said: "Are the Monster Raving Loonies committed to Crossrail? If so perhaps they are more serious than the Lib Dems or Tories.
"The Tories have already admitted they may scrap Crossrail. That would be a disaster for London and risk thousands of jobs.
"I am not sure who is the real Monster Raving Loony Party."
The £16bn Crossrail project would link counties west and east of London by train.
Conservative shadow minister for London Justine Greening said earlier in the week that although the party was in favour of it, it could not guarantee the project.
Responding to the Loonies' plans, a Conservative spokesman said: "A Conservative government would have the energy to deliver the changes needed to improve our transport. For London that means we support Crossrail.
"Londoners face a clear choice of five more grim years of travel under Labour or change with the Conservatives."
A Lib Dem spokesman said: "The Liberal Democrats are the only party committed to protecting public transport in the capital, to ensure that we move towards a green, sustainable future.
"We will reverse Labour's inflation-busting increases in fares and ensure that regulated fares rise by less than inflation each year."
The Monster Raving Loony manifesto also calls for buildings to be fitted with air conditioning units facing outward to combat global warming.
They demand that all politicians be permanently painted the colour of the party they represent.
A list of confirmed candidates for Hackney North and Stoke Newington:
Diane Abbott, Labour
Keith Angus, Liberal Democrat
Darren Caplan, Conservative
Matt Sellwood, Green Party
Suzanne Moore, Independent
Knigel Knapp, Monster Raving Loony Party