Engineering a Carbon Fiber Front Beam & Longeron from America’s Cup Masts

/ Boat Systems and Upgrades, Paikea Refit, Paikea's front beam, Working with Composites / By

Key Message: By repurposing high-modulus carbon fiber from America’s Cup masts, we engineered a custom front-end system that is lighter, stronger, and far more functional than the original, unlocking new sail options and improving overall performance.

Author: Shayne & Anna

Introduction: A Dual Project Under Pressure

This project captures the essence of our refit philosophy: ambitious, resourceful, and on a deadline. With a two-week window before a scheduled haulout, we undertook two major upgrades in parallel: Anna recut a large RC44 spinnaker into a fractional asymmetric, while Shayne engineered and built a completely new carbon fiber front beam and longeron to fly it from.

1. The “Why”: Unlocking Performance and Versatility

The original aluminum front beam was a functional but limiting component.

  • Lack of Options: It provided no attachment point for an inner forestay (for a storm sail or trinket) and no bow sprit for flying modern asymmetric sails like code zeros and gennakers.
  • Weight Savings: Replacing heavy aluminum with carbon fiber contributes significantly to our overall weight reduction goal.
  • The Goal: To create a robust, integrated system that would serve as a strong anchor point for the rig and a platform for a larger, more versatile sail plan.

2. The Material: Recycled America’s Cup Mast Sections

The core of this project is the material itself: sections of mast from a former America’s Cup challenger.

  • Provenance: This is the same high-modulus carbon fiber used in the rotating wing mast we built previously, offering an incredible strength-to-weight ratio.
  • The Design Challenge: We had to work with pre-cut sections. The longest piece (the top mast section) became the longeron (bow sprit), while two thicker, shorter sections were used as the port and starboard beams that connect through the hulls.

3. The Build: Precision in the Grinding Bay

The construction was a masterclass in composite fabrication under time constraints.

  • Complex Geometry: Joining the cylindrical mast sections at precise angles required meticulous cutting and fairing. Shayne used a custom “secret brew” of milled fibers and filler powders to create strong, non-cracking coves in the structural joints.
  • The Pressure: The project was a race against the clock, needing to be structurally complete before the boat was hauled out for hull work. This included gluing new core into the deck and ensuring the entire assembly was perfectly aligned.

Conclusion: A Transformation Achieved

Despite the pressure, the project was a success. The new carbon structure is not just a replacement; it’s a fundamental upgrade that changes Paikea’s capabilities. It’s lighter, stiffer, and now provides the dedicated attachment points needed for a modern sailing inventory, from storm sails to performance-reaching sails.

Further Reading on the Project Paikea Refit

Interested in our front beam project? See the rest of our videos:

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