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After several strakes were attached, frames were installed—curved timbers running across hull from one side to other, providing internal reinforcement, maintaining hull shape, distributing loads from mast and deck.
The Shaping:
Frames were not bent from straight timber but selected or carved from naturally curved wood—finding trees or branches that grew in appropriate curves, cutting them to preserve natural shape. This “grown frames” approach used wood’s natural strength along grain, produced frames that were stronger than bent ones where bending compressed or stretched fibers.
The frames were spaced regularly along hull’s length—closer together amidships where stresses were greatest, farther apart toward ends where loads were lighter. The spacing reflected understanding of structural requirements despite lacking formal engineering analysis.
The Attachment:
Frames were not nailed or spiked to planking—instead, they were lashed with spruce roots or other flexible cordage, tied through holes drilled in projections carved on planking’s inner surface (cleats). This lashing allowed flexibility—frames could move slightly relative to planking, preventing stress concentration that rigid attachment would create.
The lashing had to be maintained—checking periodically that it remained tight, re-lashing where cords had stretched or worn, ensuring frames remained properly positioned. Loose frames meant hull shape distorted, potentially causing performance problems or structural issues.
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