New Nacra F18 “Evolution”: Q&A with Bob Hensen & Fer van West

by CSN · Published October 21, 2019 · Updated April 25, 2020

Click images for slideshow & orig size – Nacra F18 “Evo” Just when you thought Nacra was letting go the Class that helped them become what they are today with Olympic N17 & youth N15 officials Cats, the Dutch based yard launch a brand new F18 Design by Morrelli & Melvin. MM also delivered the now legendary Nacra Infusion back in 2006. Find below your QA for the new F18 done with CEO Bob Hensen , 2x F18 World Champ & Morrelli & Melvin designer / Naval Architect Fer van West.

Nacra F18 Evo 2019 – Q&A with CEO Bob Hensen & Ferdinand van West

– CSN: Nacra dominated the scene in the first part of the 2010s and grabbed by now 5 Worlds: 2008, 2009, 2013 , 2014, 2015. Now the Exploder Scorpion achieved 3X Titles in 2019.
Good to see Nacra putting emphasis on the F18 once more, as the F18 Class is the core base and foundation of the company current success. When this new F18 was conceived? Bob Hensen : “The Nacra F18 infusion was indeed our foundation after the Inter range. As you already said the infusion had a really strong position in the F18 fleet and brought big success. After last year change of management, there were off course also changes in strategy with renewed focus on the F18-class.

The brand “Nacra” will celebrate her 45^th anniversary in 2020 and this was for us the moment to put all years of experience in this new project. As supplier of two Olympic classes for several years now. We want to fight our way back in formula classes. Starting with the launch of the F16 carbon followed by a (r)evolutionary F18.

May 2019 the F-18 design was finalized in corporation with Morrelli&Melvin. After that the test program started. “

– The MK3 was not launched a bit on a hurry now seeing this new F18 launch in less than a year?

Nacra Bob Hensen : Peter Vink and Morrelli&Melvin took their time for this project. Pete Melvin and Ferdinand van West started already this project at the Worlds in Sarasota and they brought back a wealth of data from the event which they applied directly to the drawing board.

– Now the MK3 will be continued to be offered with the convertible package, but this new F18 don’t. Reason?

Bob Hensen : The F18 Evolution is specially designed for class legal events. As you said yourself the competition is big. With this F18 Evolution we return on the podium of the top level in the fleet. The Nacra F18 Infusion will be available as the ultimate allrounder in the F18-class. Full foiling and class legal. The F18 fleet gives so many opportunities for a wide range of sailors, in this way Nacra can offer a suitable F18 for everybody.

– Rigging and details look neat as always from Nacra. Which will aprox sell price when launched officially?

Bob Hensen : “Thank you! Rigging and details are really important for us. This will grant the customer a complete and ultimate sailing-experience. The F18 Evolution will be offered, complete with all options for €22.925.- ex Vat ex Works. What does Nacra mean with complete with all options? Well almost everything, the boat is complete race ready, sails, wing trampoline, racepack, covers, race rigging, systems, carbon FRP rudders and Carbon FRP daggerboards. The only additional options that are not included in this offer are a beach trolley, stern supports and 1:12 GP Harken system.

– When will be available for gral public? Bob Hensen : “After finalizing the test program and considering the production schedule, the first Evolutions will be ready for delivery end of February”

– First event / regatta tentative for the Evo? Bob Hensen : “We want to show our new F18 Evolution on all big F18-events, but the first big showdown will probably be Eurocat Carnac.

– We imagine it will be present for 2020 Worlds. Riders defined? Any chance for Gunnar & Fer to race again together? Bob Hensen : “We will definitely be present at the Worlds, as far as we are concerned with more than one boat. There is so much new young talent emerging, that we will probably arrange for a balanced mix between younger and older riders. No names are booked yet, nothing is set in stone yet. I don’t know the schedule for Gunnar and Ferdinand, if they are available. You never know what the future will bring”.

DESIGN Aspects

– Within an era where foils are the main performance aspect is nice to see how the archimedean mode continues to be refined.
Tell us who were involved in the design and describe the development process for this new Nacra F18

Ferdinand van West / Morrelli&Melvin: “It has been great to get involved again with this project in the Formula 18 class. The box rule of the F18 and Nacra Sailing’s desire for the best performing boat are the perfect ingredients for us designers. The main focus for us was the development of the hull shape, since the Nacra Infusion was designed back in 2005, and we’ve had a lot of ideas we wanted to try out since then. One area that has seen a major influx of development is in our use of Computational Fluid Dynamics (CFD) as a design tool to investigate new ideas, understand the forces developed, and visualize the detailed flow structures within.

At Morrelli & Melvin, we have been using NUMECA’s FINE/Marine CFD software for about five years with our in-house simulation specialist, Andrew Bloxom. Their RANS code is well proven and has been utilized by several America’s Cup teams over the last couple cycles. A good CFD department is one half of the equation, and is balanced by how you couple the results together with real world knowledge and experience to push the design envelope.

Our approach for the hull shape of the Evolution can be set out in three phases:

1) Developing the strategy to define which real world sailing parameters to focus on for hull form optimization, deciding how many run variations (think $$ here), and which of the six degrees of freedom of motion you allow for your analysis.

2) Running the various hull form candidates for each condition in CFD.

3) Analyse the results and rank them in our developed Race Model based off of VPP results and the drag derivatives from CFD. In the Race Model you can further refine the design strategy by weighting the results for different wind conditions and course headings.

Between Ferdinand and Pete, we drew and analyzed about ten different shape iterations, using the Infusion as a baseline for comparison since we know its shape and performance well. In the end we think we have developed a hull that will be better in all conditions.

Besides the development of the hull shape, we also spent significant time on the general arrangement of the sailplan and the positioning of the beams and daggerboard, as well as the development of a new higher aspect rudder with updated foil sections.”

– After seeing initial shots, we have identified that the EVO willl feature same MKII daggers & rudders. This will remain for public sales? Fer van West: There will be new rudders on the production model, daggers will remain as MKII.

– Daggercase has been moved already in the MK3, which was the goal in moving the case forward? (Like the Nacra 17 MKI , the rest of F18 are already there as C2 camp has do the same following Wildcat/Phantom/Scorpion/Edge/Cirrus.)

Fer van West: The daggerboardcase positon is more related to lateral balance then anything. The Nacra Infusion Mk3 saw the daggerboard-case moving forward to balance out the new sailplan with the trampoline endplated Mainsail and wanted to improve the performance of the Nacra Infusion upwind in the light conditions.

– When we heard the news of a new Nacra F18 , we envisioned that the Nacra F20FCS / N17 hull was going to be used as a base, seeing preliminary shots, seems the case for the bottom. Which are the main differences with the Infusion hull, which is a very good allrounder and similarities if any to the F20/N17.

Fer van West: “As you said before the Formula 18 is still very much in Archimedean mode, whereas the Nacra F20 and Nacra 17 hull shapes were more based on transitional semi-foiling to full foiling modes where the rudder and daggerboard foils assist the hull form with vertical lift. Therefore, the Nacra Infusion proved to be the base more then anything for this project, in particular if you look at the impressive track record Infusion holds. I am certain that with a good team the infusion would still be competitive today, however our aim is to improve the Infusion all-round in all conditions with the Evolution. There are many differences between the Evolution and the Infusion but for the naked eye I believe the main differences lay in the rocker shape and volume distribution.”

– The new Evo features transom chine and a bow rail, the rails purpose has always been to keep water going up the freeboard thus reducing the wetted surface, and hard chines, as used in the Edge (but swapped, rail in bow, edge in transom) seeks to push water aside. The Evo transom chine is more elevated than the Scorpion and the rails lower say then the Wildcat. Which were the goals for those design aspects?

Fer van West: “In terms of performance the hull chine of the Evolution is more related to the aft section and transom of the hull in an effort to create the right compromise between the big range of conditions from sailing upwind in the light wind with both hulls in the water to doing full speed downwind with the windward hull flying. ”

– Font beam has maintained Infusion advanced position or has changed?
Fer van West: Relative to the Infusion we moved the front beam slightly aft and the Aft beam slightly forward, which is primarily driven by the updated Aero package of the Evolution. Beside the beams we also improved the positioning of the Forestay bridle tangs into the hull.

-Which other aspect was focused to improve performance?

Fer van West: “Aside the rudder shapes we focused on the new Aero package of Performance Sails and all sorts of revised and improved details all over the boat from the hull laminate construction to the running rigging. “

– Additional comments :
Nacra: “Thank you for giving us the opportunity! Cat Sailing News has always been a big promoter of the Formula 18 class. It is very encouraging to still see the big turn ups to all the F18 worlds and we hope that with the launch of the Nacra Evolution to empower the Formula 18 class even more!”

—–ENDS——