North Sails NEWS


Episode 3 of Our “What is…” Series Focuses on How The North Design Suite™ Powers AC75s

📸 ACE | Studio Borlenghi

In episode three we get technical again and aim to answer a burning question: what is the “Engine Above Deck”? You might think it’s a pretty straight forward answer (no, there’s no literal engine). And, at first it kind of is, but once you dive into it, it’s actually quite complex. Press play to learn all there is to know.

We know now that when flying, the AC75s experience considerably less hydro-drag compared to conventional boats, but to go from floating to flying you need a lot of horsepower. And that’s where the term ‘Engine Above the Deck’ comes into play. The term refers to integrating the aero– the North 3Di sails, the Southern Spars rig, and Future Fibres rigging– with the boat’s hydro package: the AC75’s hull and foils. In the 36th America’s Cup, all the systems, from the rig to the twin skin mainsail and its control system, to the foils under the water were designed to work in harmony to maximize performance potential.

To make this happen, you need the North Design Suite software. The design suite is a powerful piece of software that is able to build a 3D shape of a sail and rig to determine the flying shapes, as well as the stresses and strains going on in the sail and rig. All sail designers at North Sails, including the embedded team designers working in the America’s Cup teams, rely on the five different programs within the North Design Suite to build their team’s AC75 sails: DESMAN, SPIRAL, WARPS, FLOW, and MEMBRAIN. Throughout the AC36, the software was rapidly developing to meet the sailmaker’s needs.

North Sails invented the scientific approach to sailmaking and, today, the North Sails Design Suite™ is the most powerful and diverse sail design tool in the industry. The cool thing about the whole process is that it’s not just a tool for the elite designers to play with; it ultimately trickles down and benefits all customers– including those who enjoy Wednesday night racing and weekend cruises.

There’s so much more to it, and we promise you there’s even more to talk about… this is only the abridged version! Watch the video and find out more about the Engine Above Deck and North Design Suite.


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