The sunnmörsåttring was an older type of boat, open and clinker-built. The normal length of these boats was some 35 - 40 feet with corresponding beam from approximately 8.5 to 9.5 feet. The åttring usually had a crew of 6-8 men. As you can see from the drawing, the åttring was originally equipped with a single, specially designed and unsymmetrical square sail. I guess this sail must be an ultimate development of square sails, whose origin can be traced back perhaps some thousand years or so.
If it wasn´t for the yard, an åttring-sail could be classified as staysail, not unlike a Genua-foresail. The yard - although short - had a safety aspect of great importance for these open boats - it lowered the sail´s center of effort.
Boats equipped with this single-sail rig were both well-sailing and well-balanced. However, when tacking, there was a main draw-back - the crew had to lower the sail and set it again with the yard on the other side of the mast. A well-trained, experienced crew was needed to carry out this maneuver properly. Later on, from 1865, many of the åttring-boats were re-rigged with a kind of lug or gaff sail.
When Norwegian fishermen realized the great advantage of using sailing vessels, the åttring turned obsolete. The boat went out of use so quickly during the first decade of 1900s that one museum some years later had to order a newely built copy from a well-known and skilled craftsman.
The original drawings shown in this chapter were made by Bernhard Færöyvik, who in 1932 made an accurate documentation of an åttring.

The midsection of an åttring was usually located at some point between 35% and 38% of the waterline length abaft the stern - a location corresponding well with the sail´s center of effort. The mast was placed nearly amidships.