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Measurement Center

Measurement Center — The 4-Layer Protocol

Section titled “Measurement Center — The 4-Layer Protocol”

Traditional measurement forms list 50-80 data points in a flat table, making it easy to miss critical dimensions or get overwhelmed by details. Our approach is different.

Core principle: “Big picture first, details follow.” We organize measurement into four logical layers, prioritized from most critical to least.


Defines how big the sail can be. This is the most critical data — it sets the geometric boundaries. If L1 is wrong, the sail won’t fit the rig.

  • Focus: Maximum possible space
  • Key data:
    • Mainsail: P (Luff max), E (Foot max)
    • Headsail: I (Foretriangle height), J (Foretriangle base)
    • Verification: Pythagorean check (diagonal stays)

Defines what shape the sail can take. Within the geometric frame, how much roach is possible? Will the leech hit the backstay?

  • Focus: Sail-to-rig interference
  • Key data:
    • Backstay: Determines mainsail roach and head width
    • Spreaders: Length and sweep angle — affects headsail and mainsail clearance
    • Mast Bend (Pre-bend): Determines mainsail luff curve

Defines how the sail attaches. The finished sail must physically connect to the boat. This is the “interface” layer.

  • Focus: Connection points
  • Key data:
    • System: Slides / Cars / Bolt rope
    • Corners: Tack, Head, Clew — specific connection method (pin diameter, cutback, offset)
    • Deductions: Hardware fitting allowances

Defines durability and ease of handling.

  • Focus: Where does it need reinforcement? What needs clearance?
  • Key data:
    • Protection: Spreader patches, lifeline height
    • Handling: Reefing type, furler drum height

The thinking behind the 4-Layer approach. Why it works, how to use it in the field, and common mistakes to avoid.

Step-by-step mainsail measurement following the L1→L4 protocol.

Headsail and furling system measurement, including foretriangle geometry, furler compatibility, and UV coverage.

(In development) Spinnaker and Code Zero measurement procedures.


  • Products — Sail systems that these measurements feed into
  • Components — Hardware specifications referenced during L3 measurement