Introducing the Bieker Moth V2 (BM-V2)

Introducing the Bieker Moth V2 (BM-V2)

Introducing the Bieker Moth V2 (BM-V2)

If you feel like the Moth class is on a never-ending development trajectory, you’re not wrong. The quest to squeeze "just a little bit more" in performance is a constant factor in this Class. The Bieker Moth is no exception.

While we know the Bieker Moth already provides a winning formula, we have undertaken a review of the boat using sailor feedback and our learnings to date.



The review has focused on perfecting details which we believe provide some real performance gains. The result is the Bieker Moth (BM -V2), a true Bieker speedster.  Check out the changes and mods to the Bieker Moth below:

BM-V2 Hull and Beam moulds  

A new BM V2 hull mould has been built from a hi-temp carbon tooling prepreg. This offers perfect structural properties for keeping the stability and accuracy of the mould for a longer period in a production environment.  

The BM-V2 mould will improve the accuracy and consistency of the hulls coming off the mould which ultimately means lighter hulls and precise alignment of all the components.  

The V2 mould keeps the current hull shape as we believe this shape continues to provide an aerodynamic advantage.  

The V2 also incorporates a new beam mould, also made of the hi-temp carbon pre-preg. As with the hull mould, the V2 beam mould offers greater accuracy and consistency with less finishing detailing required. This means less weight added in the finishing process. 

It’s also a win-win from a sustainability perspective as the extra investment in the material used in the new moulds will mean a much longer mould life span. 

BM-V2 Hull laminate 

Extensive R&D was undertaken on hull laminate options that could reduce weight while retain stiffness. The result is the use of a new custom-made spread tow tri-axel pre-preg carbon fibre which has reduced weight while adding torsional stiffness. High load points have also been reinforced with unidirectional carbon fibre patching. 

V3 Gantry Mould 

A new gantry design and new 3-point attachment system to the stern will further enhance light air performance. The new shape will produce minimum volume along with a reduction in weight. CFD analysis also revealed no increase in aerodynamic drag compared to the V2.  As per the Class rule, the gantry is not water - tight. It will hold minimal water, including when the boat is at rest.  

While there is the possibility of retrofitting a new gantry to a V1 Bieker moth, this would require a degree of boat building skill. 



V2 Flight Control System  

The weight and tolerances of the flight control system has been improved, from the paddle through to the flap.?Geometry between wand head and gear lever has been modified to half the height of the “bubble” in the deck fairing along with reducing the change in ride height when adjusting gearing.  

The result is an improved deck seal between the sail and deck that produces yet another aerodynamic gain.  

V2 Skinny mast post 

The skinny mast post is now designed to be very close in diameter to the mast section. This creates a smoother, more streamlined transition between the mast post and the mast, which produces a further aerodynamic gain. This change will also mean the downhaul is smoother to operate.  

V2 Spreader 

The spreader and attachment system has been redesigned to make it significantly lighter, while also implementing an adjustable prodder system. The manufacturing method has been changed to produce a far lighter carbon structure along with a new titanium attachment point for added strength. 


The tiller is a full custom carbon tube with a tapered laminate. It is designed to be stronger and lighter than the current tube while also built to last the test of time.  


The fastenings and connections have been redesigned, including the use of a new titanium gudgeon pin to reduce any movement, reduce bending and provide steerage precision. The rudder laminate has also been modified to improve stiffness. 

Main Foils  

The foil construction process has been continually refined and is now producing very consistent, perfectly shaped foils.  

The new MH-V6 horizontal was designed prior to the 2021 Worlds to provide greater lift from a lower speed lift off. Sailors found that while this new foil section achieved greater lift as promised, there was very little loss in top end speed. 

In-fact 28 knots is regularly achieved with this light-airs foil. They also found that the V6 is still superfast much further up the wind range than anticipated for a higher lift foil.  

New low drag V3 verticals for light airs were also developed prior to the Worlds. The V3 verticals are shorter than our standard verticals (although a similar length to most other moth foils) and also narrower which gives a weight and drag reduction.  

The V3 was used by the top three boats at the 2021 Moth Worlds.  

We now have a range of horizonal and vertical foils designed to cover a wide range of sailor’s weights and wind conditions.  

Current BM Vertical and Horizontal Foil Models: 

Model Name Conditions
MV-V2     Main Vertical-Foam HM carbon

All round

MV-V3 Main Vertical-low drag;reduced length and chord

For light airs


RH-V1 770mm Large - HM carbon Light air
RH-V2 657mm Small-Gullwing shape HM carbon All round

Main Foil Development 

We have recently made a modification to the flap laminate on the main foils to produce a stronger, more robust foil.  

Next step: The next step in our foil evolution will be based on feedback from sailors testing the V6 and V4 sections. These foils are identical in profile which gives us an excellent opportunity to validate CFD analysis on the different sections. 

Rudder Foils 

Modifications to the rudder elevator is work-in-progress and will be based on feedback and testing from sailors. The new design is likely to be somewhere between the V1 and V2. 

Current BM Vertical and Horizontal Rudder Models:

Model (Vertical) Name Condition
RV-V2 Foam filled HM Carbon All round
RV-V3 Foam filled HM Carbon, small-reduced drag setup

Light air

RH-V1 770mm Large-HM carbon Light air
RH-V2 657mm Small - Gullwing shape HM Carbon All round

For more information contact us