and how much was actually needed was a loop that produced much debate. In the end it was decided to ‘cap’ right-
ing moment at 400 tonne-metres. More was possible, but the increased loads would make the rig less efficient as it is the rig that bears most of the brunt. This yacht was not meant to be a monster, but an effi- cient, easy to sail, comfortable and fast blue water cruiser… Ultimately, a similar solution was used to
drive the DSS foil to the one used on Wild Joe. Bearing in mind that the foil alone weighs 1,125kg and servicing is something that should be done when the yacht is out of commission for general maintenance, Gurit stuck to a few simple drivers. The foil would be driven by line,
recessed in the bottom of the foil and pow- ered by a Harken captive winch developed for the task. Limiting the line pull to 20,000kg, as you only want to move the foil either to retract it, because you are not travelling fast enough, or tacking and gybing, allows this ‘low-tech’ approach. (20,000kg is the load needed to move the foil prior to gybing when sailing at 22kt. This could have been made higher, but this did not fit the philosophy of the yacht and it will usually be possible to slow down to 22kt to gybe the foil). Solid bearings were selected in place of
the titanium rollers on Wild Joe for their reliability and with a minimal loss of pulling efficiency. A series of simple mechanical stops ensure the foil sits on the bearings as designed. Technically Baltic have done an impec-
cable job of delivering a DSS package that completely meets the brief. Of course, compared with some of the very advanced propulsion and charging systems onboard it looks positively stone-age, but the benefits of DSS are about keeping it simple and making each yacht even more of a pleasure to sail.
design a structure that could not only withstand the vertical bearing reactions, but also the horizonal reactions generated through off-design load cases, which were of a similar magnitude, while all being able to be assembled in a practical sequence… and all fully concealed behind the pan- elling and furniture of the owner’s cabin.
More knock-on The traditional standard static righting moment-based methods for sizing rig and equipment design loads needed to be revis- ited in the context of this boat’s dynamic, speed-dependent righting moment, includ- ing an assessment of real-life operational constraints (something typically reserved for multihulls) to avoid the over-specifica- tion of equipment. This is the sort of challenge Baltic Yachts
thrive upon. As a company steeped in inno- vation, this now gave them, despite a few headaches, a clear reference point for their objective to be the natural home for projects where the vision exceeds the norm. And Roland Kasslin, head of design and
44 SEAHORSE
engineering at Baltic, had a vision of his own: to take something inherently compli- cated and make it as simple as possible for the end user, something that has been at the core of DSS yachts previously devel- oped by Infiniti/DSS. It was at this stage that Baltic brought Infiniti into the team. Gurit was responsible for the overall
engineering of the yacht with BAR Tech- nologies consulting on foil-actuation systems and bearing design. Using the experience of Hugh Welbourn, inventor of DSS, throughout the process often helped find the simple answer to the complex question. Undoubtedly the experience of the triumvirate of Welbourn, Gurit and Isotop, who have now produced over 60 DSS foils together, paid dividends. In simple terms the DSS foil employed is
a transverse foil not dissimilar to that used on the Infiniti 36s,
the retrofitted
Reichel/Pugh 60 Wild Joe and R/P 100 Wild Oats, but the loads were now at an altogether different level. The balance between how much righting moment was wanted, how much could be coped with
Rig and rigging A yacht such as this, with a limitless cruis- ing ground, meant a great deal of thought was required on how to ensure the boat ‘works’. Modern superyachts often now have an ‘owner mode’ and a ‘delivery mode’, the transition from regatta to delivery mode involving substantial changes to the rigging set-up and sailplan. Processes like this can take several days
and, with the brief that the yacht would need to be capable of handling all types of use, and transition from calm to storm, without a shore crew to make the alterations in the comfort of the marina, plenty of thought went into the sailplan and rig geometry. The final rig features a square-top main-
sail, allowing for a shorter mast which in turn lowers the centre of gravity without compromising sail area. However, the requirements for minimum headstay sag from both the J1 and the self-tacking staysail meant that due consideration needed to be made to ensure these were not compromised.
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