The Bieker Moth Concept

The Moth Class presents very few design restrictions so it was not surprising that the Bieker Moth became something quite radical given the diverse roots of its design team - America’s Cup I14s, foiling kites, 18’ Skiffs, Moths, Olympic classes, and involved Paul Bieker (Designer), Riley Dean (Engineer), Leopold Fricke (Composite engineer),  James Gell (Boatbuilder), Scott Babbage (development Sailor) and David McDiarmid (Mackay Boats Director).

Design and prototyping of the boat began after the 2017 Moth Worlds in Italy where focus went into minising aerodynamic drag and heeling moment. To this day, the design continues to evolve based on feedback from sailors and new ideas and improvements from designers.

The boat was Initially built by LSF Composites but in mid-2019 Mackay Boats took over the build with James Gell helping to build the first few boats at Mackay.

The Build

Producing consistency into everything we build is our goal. We adopt the processes used for our Olympic Class builds to the Bieker Moth. But there is a difference.

In other Classes, every sailor wants to feel reassured that they use exactly the same equipment as their competitors so that it is an even playing field.

Not so in the Moth Class where development and consistency are both important. 

We strive to make sure that the platform (hull and wings) we supply are the best possible and consistent. Every part is checked, weighed and recorded so we have a complete build record for each boat.

Sailors can also apply their own expertise to develop their boats further. 

Spare parts can be fitted easily and means that upgrade parts can be adapted to existing boats.

The Moth is full of ever developing parts so it is an ongoing project for us to apply the concept as each part develops.



The Hull

The centreline-joined hull is built from pre-preg carbon fibre on a nomex core. The hull is a comparatively high-volume displacement shape, with a rocker profile for easy low ride handling and un-sticky take-off characteristics.

The Deck

Designed with a deck-sweeping rig in mind, a fairing panel on the deck aft of the mast enables the sail to be sealed onto the deck.  This feature reduces drag, makes the sail more efficient and allows the boat to get the most from the end plate effect. 



Wing Beams and Solid Wings

Using minimal tramp area, the platform concept minimises aerodynamic drag and heeling moment.

Stiff single piece wing beams located in rebated deck sockets maximise effective beam when heeled to windward through a curved, high angled shape.

The wing beams are high modulus pre-preg carbon, constructed as a single piece using bladder moulding. They are designed to eliminate the need for compression struts and unnecessary joins. This rigid wing frame also reduces windage and streamlines the platform.

The solid wing option reduces aero drag and makes the boat faster to tack and gybe.  This wing also enables sailors to impart kinetic energy into the boat during tacks and gybes.


Internal Take-ups and Controls

The take-ups from the control lines have been designed to run inside the solid wing which further reduces drag. This concealed control system along with the control line configuration makes for a clean deck layout.



The foils are made from high modulus pre-preg carbon with foam cores in the verticals for incredible stiffness. Using state of the art production techniques, the single piece foils are cured at high temperature and pressure with precision alloy tools. The foils come faired, finished and ready to race.

The Team

The team behind the Bieker Moth capitalises on a diverse background in high performance boats, from the America’s Cup to i14s, foiling kites, 18’ skiffs, Moths and Olympic classes.

  • Paul Bieker- Yacht Desginer
    Seattle-based Paul Bieker has been a pioneering designer in the i14 class, with multiple World Championship winning designs over 2 decades. Paul’s foils were instrumental in the i14 transition to foil-assisted sailing.

    Paul was a designer for Oracle Team USA in the 33rd, 34th & 35th America’s Cups, collaborating on the design and structures behind the foils for the 100’ trimaran, AC72 and AC50.

    Taking a keen interest in the Moth while working for Oracle Team USA in Bermuda, Paul came up with the concepts behind the Bieker Moth and drafted the shapes, foils and structures for the boat.

  • Riley Dean- Engineer
    Riley is an 18’ skiff skipper and keen kite foiler from Auckland. As a design engineer for Oracle Team USA at Core Composites for the 34th and 35th America’s Cups, Riley has been responsible for turning design models into build processes and final parts.

    Currently working for the American Magic team for the 36th America’s Cup, Riley designed the tools and components for the Bieker Moth.

  • Leopold Fricke- Compositer Engineer                                                          Leopold is working at iXent, an engineering office based in Munich. iXent has been involved with multiple Americas Cup campaigns with Oracle Team USA. The focus of iXent’s work lies in applied lightweight construction and in particular the structural design and manufacturing of fiber composite components and systems. Leopold is a former professional 49er Skipper of the German National Team with international and national success. He enjoyed a few years in the Moth class.

  • James Gell- Boatbuilder
    James started building the Bieker Moth with LSF Composites in Whakamarama, a company he formed following his work with Softbank Team Japan in the 35th America’s Cup. James has been a boat builder for over 16 years and has extensive experience in building high performance yachts, building everything from Olympic classes, to offshore race yachts and numerous America’s Cup boats. Most recently he was a shore team member for Oracle Team USA at Core Composites, and oversaw the construction of Team Japan’s AC50.

    James worked for Mackay boats 10 years ago before starting a long career working for various America’s cup teams on leading edge composite construction.

  • Scott Babbage- Development Sailor
    Scott has been a Moth class stalwart for the best part of 20 years, finishing 10 times in the top 10 at the World Championships. Scott and Riley met in the 18’ skiff, where Scott was a 5 x JJ Giltinan winner as sheet hand on board the highly successful 7 team.

    Working as the Performance Coach for Softbank Team Japan in Bermuda, Scott was kept head down in data, figuring out how the AC50 worked and often liaising with Paul when analysing the performance of the Japanese boats.

    Scott approached Paul, Riley and James to collaborate on the Bieker Moth project. Keen to take the Moth to the next level, Scott developed the broad concepts for the boat. Scott knows how to sail a Moth fast, and will be the test pilot, putting the boat through its paces.

  • David McDiarmid- Mackay Boats Director

    David McDiarmid joined the moth team mid 2019 and has taken the lead for Mackay Boats. He is perfectly suited to this high performance environment being the current and 3 times 18ft skiff champion. David is also responsible for the operations and fit-out at Mackay Boats.

    The first thing David, Scott and James did was to develop a solid Wing option to reduce aero drag and to make the boat faster to tack and gybe through the more direct energy that the solid wing gives the sailors as they execute the gybe and tack.

    David has also refined the fit-out and take-up systems and together with James has added the aero fairing aft of the mast over the various systems which better end plates the deck sweeping sail getting the most out of the full aero package.

Buying a Bieker Moth

Please go to our on-line shop to view prices and the ask for a quote.

Complete an on-line order including the various options you want and then we will come back to you with a quote and delivery date. To confrim the order you will need to send a deposit.


World Sailing Licensed Builder
Member of NZmarine



Mackay Boats Ltd

  • 24 Manga Rd, Silverdale
  • Auckland, New Zealand
Mackay Boats are on Facebook