Standards: Costly Hurdles or Vital Guidelines?


point loads

The ISO 12215 standard gives designers and builders a detailed baseline for scantlings and specific guidance regarding material selection, workshop practices and structural details pertaining to hulls, decks, rudders and rigging for mono and multihulls. These scantling guidelines relate to specific skin pressures on the hull and stresses and strains that if not appropriately addressed can affect delamination and lead to structural failures. The codes are a complex amalgamation of data, but the University of Southamptons Wolfson Unit has recently developed a software program called HullScant that makes ISO compliance for builders and designers easier to work with. It auto-calculates the effect of thicker skins, added transverse and longitudinal support, and any upgrades in material choices, giving designers and builders a quick and user friendly means of determining what it takes to meet the structural requirements of A, B, C, and D vessel usage categories.

Though not perfect, ISO 12215 affords an analytical approach to engineering and boat building, and more importantly, boat buyers/owners get an idea of how strong the structure thats keeping them afloat happens to be. These are living documents and have and will be amended as new data and new materials enter the trade.

Key parts of ISO Structural Guidelines:

  • 12215-5 Hull construction and scantlings (monohull pressures on skin and calculating stresses);
  • 12215-7 Hull construction and scantlings (multihull version);
  • 12215-8 Hull construction and scantlings (rudders);
  • 12215-9 Hull construction and scantlings (appendages and rig attachment);
  • 12216 Hull construction and scantlings (strength of windows, port, deadlights, doors).
Darrell Nicholson, editor of Practical Sailor, grew up boating on Miami’s Biscayne Bay on everything from prams to Morgan ketches. Two years out of Emory University, after a brief stint as a sportswriter, he set out from Miami aboard a 60-year-old wooden William Atkin ketch named Tosca. For 10 years, he and writer-photographer Theresa Gibbons explored the Caribbean, crossed the Pacific, and cruised Southeast Asia aboard Tosca, working along the way as journalists and documenting their adventures for various travel and sailing publications, including Cruising World, Sail, Sailing, Cruising Helmsman, and Sailing World. Upon his return to land life, Darrell became the associate editor, then senior editor at Cruising World magazine, where he worked for five years. Before taking on the editor’s position at Practical Sailor, Darrell was the editor of Offshore magazine, a boating-lifestyle magazine serving the New England area. Darrell has won multiple awards from Boating Writer’s International, including the Monk Farnham award for editorial excellence. He holds a U.S. Coast Guard 100-ton Master license and has worked as a harbor pilot and skippered a variety of commercial charter boats.


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