Diam 24 One Design Class Rules – Chapter 1: Sails, the “Engine” of the Boat!

Since the Diam24od measurement rules partially resemble those of other monotypes, we thought it would be useful to summarize the essentials to better understand their philosophy.

This is the first episode in a series dedicated to the “Class Rules.”

Let’s start with what makes the boat move: Sails, the engine of the D24od!

 

1 – Strict One-Design: The DNA of the Diam24od

Racing in a one-design class ensures competition on “equal terms.”

Strict one-design requires that everyone sails the same boat and the same sails!

This choice was a natural decision from the very beginning of the Diam24od project.

Advantages of this approach:

• Fairness: Race without worrying about the quality of your sails compared to others. This allows you to focus fully on sailing — a true mental comfort!

• Time-saving: No need to spend hours chasing minor sail optimizations that won’t make a real difference. Better to sail than tinker.

• Mass production: High-performance, durable sails at a good value.

• Availability: New sails are readily available in stock.

 

2 – How Production Is Organized: A Quality Process

Contrary to popular belief, producing the exact same product repeatedly is challenging.

We have organized sail production according to a quality process, applied from raw material sourcing through all stages of manufacturing, including compliance and quality checks.

Each sail is produced in collaboration with a sailmaker under a supply contract that defines the sails and sets obligations for the manufacturer (raw material inspections, in-process quality control, serial production, clearly defined methods…).

At the end of production, each sail receives a serial number, stamps on the assemblies, and P.O. labels on battens or cables.

All sails undergo a compliance inspection.

Once approved, each sail is recorded in the Diam24 One Design parts database (linked to its serial number).

It then becomes available for use and can be registered on a Diam24od Certificate of Conformity.

Serial numbers combine the year of production and a unique number.

When renewing sails, they are associated with the boat via the Certificate of Conformity.

The annual limit on new sails is applied when a sail is assigned to a D24od for the first time.

 

3 – From Production to End-of-Life: Philosophy and Choices

The sail production process reflects choices that ensure high performance for the D24od and maximize durability, both in shape and mechanically:

1. Performance must remain consistent over time.

2. Sails are the engine of the boat. Supply contracts are renewable and open to improvements beneficial to the Diam24od.

3. Sails must be as durable as possible while staying cost-effective.

4. Sails wear out (shape and structure). To stay on equal terms and control budgets, the rules limit one new sail set per boat per year.

5. Changes and upgrades may result from the builder or user requests.

Notes:

• Teams manage both new and older sails on their Certificate of Conformity.

• It is possible to list all sails on the certificate and swap them depending on the weather to preserve them.

• Second life: Consider resale! Recreational sailors often buy used racing sails at a good price — better for the planet .

• End of life: Report the sail’s serial number to the class for destruction to prevent fraud.

 

4 – History of Diam24od Sails

2014: First sail set

• Main 2014: membrane, 7 Fiberfoam battens, smaller head and foot (Manufacturer: All Purpose)

• Jib 2014: Pentex, smaller than later versions, 2 battens (Manufacturer: Incidence)

• Gennaker 2014: Stormlight, designed as both Code 0 and downwind gennaker. Experience led to redesign.

2015: Updated size, shape (today’s version), and materials

• Main 1517: membrane, 7 carbon battens (Europsail CH)

• Jib 1517: 3DL membrane molded (North)

• Gennaker 1517: ZL00 (Europsail CH)

  Note: The Tour Voile gennaker is the same as the class gennaker. No compliance inspection; issued at the start of the tour and considered compliant/OD at the end. No serial number.

2016–2017: Only Tour Voile gennakers changed material (nylon).

2017: Lac rig introduced, including a Code 0 and a top gennaker. These sails are not part of the “Diam24 One Design” rules (“sea” set).

2018: All three sails updated with new materials

• Main 1823: 3DI molded, 6 carbon battens (North)

• Jib 1824: 3DI molded (North)

• Gennaker 1819: membrane (All Purpose)

  2020: Gennaker manufacturer changed

• Gennaker 2027: CZ05, very thin membrane (Europsail Evo)

  2024: Main sail manufacturer changed

• Main 2427: membrane, 7 carbon battens (Europsail Evo)

  2025: Jib manufacturer changed

• Jib 2527: Tyra, bi-radial cut (Europsail Evo)

Note: Despite minor differences due to weather, no objective loss of performance has been observed.

 

5 – Current Sails: Detailed Overview

 

 

Main 2427

• Same shape as previous mains

• ES-GP Film-Film 1.0/1.0 membrane, Black Twaron 16500 DPI fiber

• Area: 24.44 m²

• 7 carbon battens, 1 reef, 1 window, telltales

• Note: markings now black for better visibility

 

 

 

 

 

Jib 2527

• Same shape as previous jibs

• Tyra PLY TP10HRLS – TP07HBLS, radial cut

• Area: 9.44 m²

• 2 battens, 1 window, telltales

• Note: very stiff material (does not deform) but outer surface is fragile → do not roll tightly

 

 

 

 

 

Gennaker 2027

• Same shape as previous generations

• CZ05, radial cut

• Area: 37 m²

 

 

 

 

 

Availability: All latest-generation sails are in stock at ADH Inotec, the exclusive Diam24od and One Design parts distributor.