Mr McNeill will test the Qajaq in Svalbard, Norway, later this year
An Arctic explorer has taken to the River Thames to test a home-made vessel built for his next expedition.
Jim McNeill, 48, of Windsor, Berkshire, designed the boat - which he has called a Qajaq - for terrain made treacherous by melting ice in the Arctic.
He nearly died in 2006 when he plunged through thin ice into icy water while trying to reach the point verified by Nasa as furthest from any land mass.
He plans to make a second attempt in 2010 to reach the same destination.
He said the Qajaq tested well in the Thames, but it will face a sterner challenge in the icy extremes of the Arctic where temperatures can fall to -45C.
"I have been exploring the Arctic for 25 years and in this time I've seen the dramatic effects of global warming," Mr McNeill said.
"It used to be one solid sheet of ice that you could walk across.
"Now it's interspersed with stretches of icy water - if you look at it from satellite images it's like crazy paving, hence the need to build the Qajaq."
The vessel is fitted with runners and acts as a sledge for dragging the kit and equipment of his four-man team.
Mr McNeill will be doing research measuring the effect of climate change
His brush with death during his 2006 attempt made the married father-of-three all the more determined to complete his scientific research measuring the effect of climate change on the Arctic.
Mr McNeill said his "long-suffering" wife simply met the news that he would be returning to the Arctic for his 50th birthday with a shrug and the word "gosh".
"Of course [the credit crunch] had an effect on funding, I'd be lying if I said otherwise," he said.
"But it's about explaining to people the importance of our work - global warming is bigger than business, it's bigger even than politics."
Later this year, Mr McNeill's Qajaq will be put through its paces in Svalbard, Norway, where conditions better replicate the extremes he will face in the Arctic.
Jim McNeill explains his self-designed 'Qajaq'