Hi Les

Have you read Tim Severin's book? It's such a long time since I read it that I can't remember the details. But the whole purpose was to find out whether it was possible or not. This was a result of 'accounts' of an original Brendan voyage. The book will almost certainly deal with what those 'accounts' are or were. A few years ago it would have been a simple matter of waddling off to the library to borrow the book. Now the first problem is find a library.
Stan