Developable Surface Boat Designs

While overseas recently, we visited the Viking Ship Museum and workshop at Roskilde, Denmark.  What a neat place!  They have a museum containing the remains of five Viking ships from about a thousand years ago which were carefully excavated and preserved.  A display illustrating Viking history during the ascendant period is also included.  They also have a workshop in which new Viking vessels are being constructed using the same materials, tools and techniques as the originals.  Rides in these authentic vessels are offered out on the bay using both sail and oars.  Lastly, is the book store providing reference materials, and souvenirs.

Ancient Viking vessel preserved in the climate-controlled museum.

New Viking ship being constructed on site.

Plenty of enthusiastic boaters ready to go out on the bay in their Viking ship.

Reproduction of a Viking warship.  The merchant ships are wider, deeper, with less rowing stations.

This authentic Viking hull, about 100 feet long, is getting some needed maintenance.

Roskilde is a short train ride from Copenhagen's main train terminal; a nice excursion from the central city.  You can walk from the Roskilde train terminal to the museum:  Walk through the pedestrian shopping area (on your right as you arrive) toward the tall cathedral steeple, then walk down the hill, through a park to the museum on the bay.

Back to my own efforts at home:

Fairing started at the ends of the hull.  Because I had used a parallel projections to create the hull, all ruling lines are parallel.  For the garboard the x/y/z projection is 12/4.8/1.6 (12" spacing of frames) which I could mark in pencil on consecutive frames and then use an angle grinder (needed aggressive abrasive cutting) to remove excess material, stopping to check my work by laying a straight edge at the angle of the ruling lines.  With the closely spaced frames, stringers and stem profiles as guides, this fairing was not too difficult.

Fairing of the bow area; a batten has been laid in place to demonstrate the direction of one of the ruling lines.  If the projection in this area is conic instead of parallel, the ruling lines can still be plotted (using the intersections at the keel and frames), but may be more time consuming.

Next to do was fairing of the frames and stringers.  This is fine work, more appropriately done with a plane in most areas.  Because the dimensional changes at this point are minor, I could start making patterns for the future hull sheathing.  The garboard pattern is widest of the projected chine areas and curves downward toward the hull ends; thus, plywood will likely be the best material to use.  I have several sheets of 6mm (5 ply) occume plywood on hand.  It is slightly too stiff for the stem curvature, but I have discovered that I can run it through my planer and make it into 4.8mm, 4 ply, which will take the curvature.  You couldn't do that with non-marine ply because of its inferior inner plys, but for marine plywood the inner plys are also high quality.

I am still looking at options for planking material for the other chines and need to make some decisions before proceeding further.