LAPSTRAKE BOATS





PRESENTED BY:
the Wanderling

CONTENTS RESEARCHED THROUGH THE WORKS OF:
HANNU VARTIALA


The golden era of building lapstrake boats was during the Viking age, sometime around years 800 to 1000.

Lots of details of buried and wrecked Viking ships and boats have been documented. The ways of construction differ from modern methods. Some seem strange, some even misguided.

Why the boats were constructed the way they were constructed has been given surprisingly little thought. It seems, that in the archaeology science it is only customary to ask "what?", but not "why?"

The purpose of the special construction details in Viking ships was to prevent the ships from breaking, by allowing wood swell and shrink freely.


Frames

The frames of many Viking ships don't stretch from sheer to keel to sheer in one piece. The frames are more like a set of frame stubs supported by a star like lattice.

The star like support lattice (red) consists of the seat, a floor support beam, two vertical supports between them and a single vertical support between the floor beam and the keel frame stub (yellow).

There is a frame stub at every point of the star. At the seat ends (pale blue), at the floor beam ends (pale green) and at the lower end of the lower vertical support (yellow).

The keel (violet) is NOT attached to the lowest frame stub (yellow) at all. The other frame stubs are attached to planking by lashings or a single nail and lashings. But the frame stubs are not attached to each other.

The construction is solid as far as pressure against ship sides is considered. Much firmer than an ordinary frame would be.

Yet it is very flexible in the direction where the ship planking swells and shrinks. Swelling and shrinking forces are opposed only by bending stresses of the seat and floor beam.


The way hull strakes meet the stems

In Viking ships the last stakes near the stems were carved out of naturally curved wood. This way the stakes meet the stems with grains almost parallel.

The stem and strake both swell and shrink in the same direction - no stresses in either member.


The way strakes are lashed to frames

Viking ship strakes were lashed to frames with sinew or spruce root lashings (tree and iron nails were used, too, of course). Vikings used a lashing something like this:

When the strake was hewn lumps of wood were left on the strake on either side of each frame location. Holes for the lashings were drilled only through these lumps, not the whole strake.

An extremely laborious structure. What's the point?

When the strake swells, the lump on the inner surface swells inward, loosening the lashing, letting the strake swell and slide sideways.

And of course, it is a good idea not to make holes in Your boat hull. It may also be nice to be able to renew a broken lashing underway without going under the ship.



KENSINGTON STONE
THE CASE FOR NORSEMEN IN AMERICA
BEFORE COLUMBUS

BUDDHISM IN AMERICA BEFORE COLUMBUS



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VIKINGS OF THE DESERT SOUTHWEST






CONTENTS THROUGH THE GRACEFUL SERVICES OF
HANNU VARTIALA author of:

HANNU'S BOATYARD



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