Building Rudders Designed for Wings: An America’s Cup Inspired Project

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Leveraging professional-grade components and techniques to fabricate high-performance rudders on a cruiser’s budget.

Key Message: True innovation in a refit often comes from creatively repurposing existing high-performance technology and combining it with meticulous, professional fabrication techniques.

Author: Shayne & Anna

Introduction

Replacing Paikea’s non-original and failing rudders was a top priority. While designing from scratch was an option, a fortunate discovery offered a faster, more cost-effective path: a set of rudders from the 2007 America’s Cup. This post details the process of creating moulds from these elite foils and the unexpected discovery that will take their performance a step further.

The Master Plug: Sourcing Hydrodynamics from the Cup


The foundation of a good composite part is a perfect mould, which itself requires a perfect “plug.” The 2007 America’s Cup rudder provided exactly that—a hydrodynamically refined foil shape developed with a level of R&D far beyond a typical cruiser’s budget. By selecting the optimal section of the AC rudder, we inherited world-class hydrodynamics for the cost of materials.

Mastering the Mould: Teflon Release and Professional Finishes

To create the female mould, we used a professional-grade Teflon release system. Unlike traditional waxes, this leaves a flawless, high-gloss surface finish on the mould without any transfer, eliminating the need for post-mould polishing. This technique, common in high-volume production, ensures each rudder we lay up will have a perfect outer skin straight out of the mould.

The Build: Foam Cores and Strategic Reinforcement

The rudders are built as a composite sandwich:

  • Pre-Shaped Foam Core: The internal foam core was pre-cut and slitted to allow it to conform perfectly to the mould’s shape.
  • Solid Glass Base: A solid fiberglass plate was integrated at the base of each rudder. This provides a robust, threaded insert point for the future attachment of the winglets, allowing for adjustment and replacement.

The Game-Changing Discovery: America’s Cup Bulb Winglets

While planning the winglets, a breakthrough occurred: we discovered the original winglets from the bulbs of the 2007 America’s Cup yachts. These components are designed for one purpose—to control tip vortices and reduce induced drag. This is exactly the function we need for our rudder tips. While they present a moulding challenge due to their complex, handed geometry, they represent a direct transfer of America’s Cup technology to our performance cruiser.

Parallel Projects: Custom Rigging and Hull Prep

Alongside the rudder work, we progressed on other fronts:

  • Spectra Strops: We fabricated custom loops from high-strength Spectra to attach our existing wire sidestays to the new rotating mast, a critical detail for a safe and reliable rig.
  • Hull Priming: The hulls were sanded, faired, and primed, a milestone that signifies the end of the major hull work and the beginning of the finish phase.

Conclusion

This phase of the project demonstrates the power of a resourceful, professional approach. By using an 2007 America’s Cup rudder as a starting point and incorporating genuine Cup winglets, we are achieving a level of performance and sophistication that would typically be cost-prohibitive, all through knowledge and skilled execution.

Want More?

This is just the beginning of our rudder journey. Check out the Paikea Refit on our Free Resources page to see the continuing evolution of Paikea’s rudders.

Want a deep dive into boatbuilding? Check out our Members Hub where we share more details on Paikea’s Upgrades and share resources you can use for your own project.

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