Imagine trying to sail from one side of the Atlantic to the other, in some of the roughest seas known to man in an open boat, in sub-zero tempartures, contending with pack ice, icebergs, whales and massive tidal races in a keel-less contraption that has more in common with a good pair of shoes (albeit shoes that are held together by flax fiber and rubbed liberally with pungent wool grease) than a yacht. All driven by his determination to prove that it was possible for early Irish navigators to reach the coast of North America and that they may well indeed have done so.
They named the boat The Brendan - which seems a bit strange when you read Severin referring to The Brendan as 'she' all the time, but that's sailors for you I guess.
You may know more of the tale of St Brendan than you think. I certainly recall hearing a tale of sailors landing on a small wooded island and setting a campfire, only to discover to their alarm that they have alighted on the back of a whale. There are lots of other, obviously mythical parts to the tale, involving griffons and talking birds but as Severin and their crew make their way via the Stepping-Stone route: from Ireland to the Faroes, from there to Iceland, from there to Greenland and finally to Newfoundland they encounter phenomena and places that are strongly reminiscent of the tale:
For example, The mythical Lands of sheep and birds at the beginning of the tale seem to correlate very well with the Faroe islands. The crew's encounters with pack ice and icebergs mirror Brendan's crew's encounter with a huge cyrstal pillar that floated through the sea. The formation of spindle ice, when the water seems to grew sticky and ponderous with growing ice-crystals that is similar to the account in the Navigatio of the sea become coagulated at one stage.
Sadly, I doubt Severin and crew would have seen half as many whales as they saw the first time if they undertook the voyage now, 30 years after the original Brendan Voyage. By his account multitudes whales of all species (including a potentially nasty confrontation with a pack of Orca) seem to accompany The Brendan wherever they went.
I had previously read The Sindbad Voyage by Tim Severin where he describes how he got a lot of rich Omani sheiks to fund a project where he built a traditional, all wood trading dhow to sail the original Arabian spice route to what is now Malaysia. Seems like this Archeo-mucking-about-in-boats thing is a bit of a hobby of his. Sounds like a great idea to me.