Sven Yrvindvideo
Stronger mast, no compresson, half the bending arm
January 20, 2026 · 10 min · 4K views
What this video covers
Sven Yrvind is modifying the mast design for his high-latitude, shallow-draft boat to eliminate compression forces and reduce bending moments. The original balanced lug rig design subjected the mast to both high compression from the halyard and significant bending leverage from the sail attachment at the masthead.▶ 2:20 To mitigate these stresses, Yrvind is installing a new attachment point at the midpoint of the two-meter mast, effectively halving the lever arm and removing the vertical compression load.▶ 3:02 The construction process involves glassing a new fitting into the mast structure using epoxy and peel ply to ensure a smooth, strong surface for subsequent layers.▶ 4:38 Yrvind is also integrating a waterproof housing for an antenna and routing 1.5 mm² wiring for LED navigation lights through the mast.▶ 7:25 These structural refinements aim to improve the rig's durability for a planned 14,000-mile nonstop circumnavigation through the Southern Ocean.
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