I know this isn't Bolger (though he did do a design for a larger Viking boat - see Boats With an Open Mind). However, I know a lot of us are interested in small boat construction in general. So I decided to post this because the monograph in question is rare and someone out there may have an interest.
For those of you who are interested in Viking boats, or may want to build a Viking faering (four-oared boat) based on the Gokstad find, a copy of the publication describing construction is on e-Bay. It's called "The Building and Trials of the Replica of an Ancient Boat: The Gokstad Faering", and it was published by the (British) National Maritime Museum.
The link is: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110478662253&ssPageName=STRK:MESELX:IT