This is insane, I would love to do something like this but I think I would only last a day or two.
These guys have done a 7k trip as well. see below
In 2003, the pair spent 57 days on personal water crafts, travelling from the Kenyan border with Somalia to Cape Town, a distance of 7000km.
They survived on a diet of fish (Adriaan is an accomplished spear fisherman) and water from coconuts. Camping sites were mainly deserted island beaches. Fuel often had to be bought on the black market at inflated prices.
Once, the crew had to divert 140km inland to secure fuel, traversing crocodile-infested streams and the mighty Zambezi River, towing rubber ducks to carry the precious cargo. They often crossed to Islands, some 70km off-shore, in search of fuel.
The land crew could not reach the shoreline due to heavy rains at the time, and with the communication items damaged, the watercraft pilots had to continue unsupported until they reached the Southern parts of Mozambique.
I will probably follow this little excursion of theres, hopefully someone keeps there site updated.
For more info go to: (super slow site)
http://www.13000miles.com