SH-Sep20-THIS Bieker hi res.qxp_S_H May Rob.qxd 23/07/2020 15:45 Page 42 At that stage Moth evolution had been rigorous structural engineering methods to continuous but incremental and Scott saw the boat to make it as dependable and stiff an opportunity to take forward some of as possible for its weight. Knife, the latest configuration improvements in Scott and I pulled together a team that the boats and incorporate them in a brand included SoftBank Team Japan boat- MARTINA ORSINI new no-compromise design that also took builder James Gell and Oracle Team USA advantage of some of the things that we design engineer Riley Dean to assist us in gunfight had learnt from our recent experiences in turning the boat into a real product. the Cup. Taking an excursion back into Throughout the next 12 months the core the world of high-performance skiffs after team was boosted by additional specialist When a leading skiff designer spending the previous three years almost FEA expertise from Thomas Hahn and who is equally renowned as exclusively working on foiling AC cata - Leopold Fricke from the composite design an America’s Cup innovator marans sounded like a nice way to wind and analysis firm Ixent, foil section analy- down from the Cup! sis from Hal Youngren and CFD analysis and structural engineer turns I had designed bits and pieces for Moths from Nico Rousselon to help us to develop his attention to the Moth class over the years – initially with innovative the design. the result is never going to be American Moth sailor Bora Gulari. That Pulling together a diverse, geographi- said, this was the first time I’d been given cally separated team for what was essen- anything less than fascinating the chance to design a complete package. tially a passion project was always going Our principal goal for the new boat was to be a challenge, but the enthusiasm and In the aftermath of the 2017 America’s evolutionary rather than revolutionary: interest from the team members, along Cup, as I was packing up our things to primarily to improve the aerodynamic effi- with persistent prodding by Scott himself, move back to Seattle after two years in ciency of the package and to increase the pushed the project along nicely. Boat #1 Bermuda, longtime Moth sailor and Soft- righting moment by increasing the length launched at the end of July 2018 in New Bank Team Japan performance coach of the foil struts as well as increasing the Zealand, some 16 months before its debut Scott Babbage came over to discuss a new height of the hiking wings relative to the at the 2019 Moth Worlds in Perth. Moth project he had in mind. hull. In addition to this, I wanted to apply At launch interest and expectations for 42 SEAHORSE SH-Sep20-THIS Bieker hi res.qxp_S_H May Rob.qxd 23/07/2020 15:46 Page 43 Left: American sailor Scott Babbage was integral to creating the new Bieker Moth but his SailGP obligations led to pauses in development. However, with two of the new Bieker Moths in the top four at their first championship, world champion Tom Slingsby (Exocet) did later concede that out of the box the ‘straightline speed is impressive… lucky for me it’s not yet matched by the boat handling!’ While the latest Exocet package used by Slingsby is the product of five years of refinement for the immaculately executed (right) Mackay-built Bieker it’s still early days the boat were high. Over 50 deposits were speed involved refining the control system Mackay Boats in New Zealand, which has placed within the first fortnight, with the linkages and getting the foil angles of the facilities and manpower to keep up challenge for James being how to both attack dialled in. In addition, the initial with orders. James Gell manages the Moth refine and problem solve the initial boat… front foil concept didn’t meet performance build team at the Mackay shop so there and then produce several years’ worth of expectations and so the team sought to has not been a loss of continuity in the forward orders at the same time. While the eliminate some of the variables by adapt- construction detailing of the boats. And prototype survived its initial launch in ing existing main foils to the longer Bieker we are continuing to improve the plat- Tauranga and sea trialling in Sydney, Moth struts. Meanwhile, Scott worked form, most recently by transitioning needless to say there were plenty of bugs to with CST Composites and Rob Green- from woven pre-pregs to ultra-lightweight be ironed out and a lot of refinement left to halgh from North Sails to develop a deck- spread tow pre-pregs in the hull, a new AP do before the boat was fully race ready. sweeping rig and sail that took full advan- main foil design which is adapted to the The boat itself was not without its tage of the clean new platform layout. recent increases in boat speed and a new, challenges. High-angled, small-area wings In August 2019 the whole concept more aerodynamic rudder pod. and long foils made it difficult for even started to hit its stride. Modifications to After that it looks as if there is room to experienced sailors to adapt to the change rig geometry, and the addition of some further improve the aerodynamics of the in handling characteristics. In fact, this dif- aerodynamic fairings, tipped the boat over rigs, especially now that the boat speeds ficulty made it hard at times to evaluate the edge. In the Sydney training group, upwind have broken into the 20s. Moths performance relative to other Moths. which included Tom Slingsby and Rob are interesting boats and a lot of fun! With Scott working in New Zealand Greenhalgh, Scott went from fighting hard with SailGP for the last few months of to having wheels. Over the next few Racing 2018, progress on the water slowed and months a mini America’s Cup of evolution The 2019 Worlds in Perth was the first the performance of the new boat remained occurred, with the group leap-frogging international event for the Bieker Moth. unclear. The potential was there, but so ahead each week with changes. By the All of the boats built over the previous were the doubts. Intense interest is a double- worlds in December the boats were regu- 18 months by LSF Composites and then edged sword for a developing concept in a larly seeing upwind boat speeds some 4kt Mackay Boats were competing, with boat- world where news gets around fast. faster than only a few years earlier. builder James Gell attending in support. Most of the work to get the boat up to Our new Moths are now being built by In Perth’s strong wind conditions the ᮣ SEAHORSE 43 SH-Sep20-THIS Bieker hi res.qxp_S_H May Rob.qxd 23/07/2020 15:46 Page 44 Fig 1 Fig 2 Fig 3 Figure 1: using a (top-end weight) sailor of 100kg all the major load cases were then considered in the optimisation process. Figure 2: rack sizing before optimisation (blue) and after optimisation (orange). Figure 3: property optimisation. Result of unidirectional laminate thickness (mm). Figure 4: final check – stress distribution is demonstrated across the rack using an envelope of the worst overall load cases. Figure 5: final check of stress distribution Fig 4 Fig 5 on hull – envelope of the worst load cases low aero drag of the Bieker gave them a Matthew Chew in eighth. Six Biekers in maximum benefits. Yet the motivation to crucial upwind speed advantage. Out of the top 15 – more than any other design. use optimisation is compelling and, in the blocks the boats would quickly and Paul Bieker, Seattle mechanical applications that we are focus- reliably establish themselves in the leading ing on here, weight saving and/or stiffness group, which then paid dividends on a Structural design and optimisation increases can be achieved without sacrific- consistent racecourse. Despite their strong Nowadays the use of numerical simulation ing the safety of the structure. And today JOSHUA MCCORMACK wind drag advantage the Bieker also won in the development of yacht structures is there are more types of optimisation avail- the lightest race of the final series on the very advanced as can be seen in the multiple able, depending on the development stage, last day, showing the platform hadn’t articles on various yacht projects in this design freedom and objectives. painted itself into a performance corner. journal. Unfortunately, however, simula- With Paul’s almost emotional connec- In hindsight the results for the boat were tion is often only used late in the process, tion to structural design it was obvious remarkable given their relative newcomer to check the final configuration for that we had to transfer these methods from status among strong, established rivals. strength and stiffness. What we have done the America’s Cup into the Moth project. While Tom Slingsby dominated the during development of the Bieker Moth is Once the decision was made to take this Worlds in his Exocet, Scott Babbage was push these simulation methods to the next path we took step after step from the con- able to equal his score in the Nationals and step of numerical optimisation. ceptual design to the final detailing, using placed fourth in the Worlds. Kyle Lang- Despite the widespread availability of suitable and different optimisation types in ford finished second overall, with this technology it is seldom used to its every stage.