ISO 12215-6:2008

Overview

ISO 12215-6:2008 - Small craft: Hull construction and scantlings - Part 6: Structural arrangements and details provides guidance on structural details and components for small craft (monohull and multihull) up to 24 m hull length (per ISO 8666). It complements ISO 12215‑5 by giving further explanations, calculation procedures and worked examples of good practice. The document covers boats built from fibre reinforced plastics (FRP), aluminium, steel, laminated wood or other suitable boatbuilding materials and establishes a benchmark for alternative arrangements using specified equivalence criteria.

Key topics and technical requirements

• Scope and purpose
  • Applies to recreational small craft (including charter craft) with hull length ≤ 24 m.
  • Supports structural design and scantling decisions not fully covered in other ISO 12215 parts.
• Structural arrangement principles
  • Stiffening systems (stringers, frames, girders, web frames, floors) and their roles.
  • Hull girder strength, load transfer and determination of stiffener spans.
  • Guidance on primary vs secondary stiffeners and grillage arrangements.
• Material-specific details
  • FRP: local reinforcement, bonding methods, laminate transitions, sandwich construction, attachment of fittings, engine seatings and hull drainage.
  • Metal (aluminium/steel): design details, end connections, increased plating, protective keel, welding and riveted/adhesive bonding good practice.
  • Laminated wood: edge sealing, plywood orientation, local scantlings and alternative criteria.
• Connections and components
  • Rudder structure and connection, keel attachment, mast support and rigging load introduction.
• Annexes and informative analysis
  • Examples for category C and D craft, shear stress in stiffener joints, recommended welding procedures, and longitudinal strength analysis.

Practical applications and users

ISO 12215-6:2008 is used to:

• Design and detail hull structure and scantlings for recreational craft up to 24 m.
• Provide manufacturing and assembly guidance for shipbuilders and boatyards.
• Benchmark alternative structural solutions using the standard’s equivalence criteria.
• Support surveyors, classification societies and regulatory bodies in inspection, certification and repair assessment.
• Aid naval architects and marine engineers when specifying stiffeners, joints, bonding and welding practices for FRP, metal or wood hulls.

Typical users: naval architects, boat designers, structural engineers, builders, repair yards, surveyors and class societies.

Related standards

• ISO 12215-5: Design pressures, stresses and scantlings determination
• ISO 12215-7, -8, -9: Multihulls, rudders, appendages and rig attachments
• ISO 8666: Principal data for small craft
• ISO 12216: Strength and watertightness of windows/portlights/hatches

Keywords: ISO 12215-6:2008, small craft, hull construction, scantlings, structural arrangements, FRP, aluminium, steel, laminated wood, stiffener design, boatbuilding standards.