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The keel was ship’s foundation—long timber running bow to stern, providing structural baseline to which all other components attached.
The Selection:
The keel required exceptional timber—long, straight, free from significant defects, ideally from single tree to avoid joints that created weak points. Finding such timber was challenging—only the largest, finest trees would suffice. The scarcity meant keel timber was valuable resource, carefully selected, transported from potentially distant locations if no suitable local timber existed.
For largest longships—drekar (dragons) measuring 30+ meters—no single tree was large enough. Multiple timbers had to be scarfed together—joined with overlapping joints secured with trenails (wooden pegs). The scarfing technique was critical—improperly made joints would fail under stress, potentially causing catastrophic structural failure.
The Shaping:
The keel was shaped to specific profile—relatively flat bottom amidships where beam was widest, curving upward at bow and stern where it transitioned to stem and stern posts. This curvature—rocker—affected sailing characteristics. More rocker made ship more maneuverable but reduced directional stability. Less rocker increased stability but made turning more difficult. The balance was craft knowledge, passed from master builders to apprentices, adjusted for intended use.
The keel’s thickness varied—thicker amidships where stresses were greatest, tapering toward ends where loads were lighter. This reduced weight while maintaining strength where needed, demonstrating sophisticated understanding of structural engineering despite lacking mathematical analysis tools.
The Installation:
The keel was laid on temporary supports—blocks or trestles holding it at working height. The positioning had to be precise—keel had to be level and straight, providing accurate reference for all subsequent construction. The stem and stern posts were attached to keel ends—massive timbers extending upward and forward/backward, creating ship’s distinctive profile while providing structural elements to which planking would attach.
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