OUTSTRIPPING THE WIND – GUNBOAT 68

July 13, 2019

Article #10 in our series about the design and build of the Gunboat 68.

Its January in La Grande Motte, with the Gunboat team out hoisting sails and loading up Gunboat 6801 for the first time. Blowing 12kts true, under full main, the J0 goes up and CONDOR immediately accelerates to match the wind speed of 12kts upwind. With that box checked, we bear away changing sails to the A3 with the boat speed increasing all the way touching 17kts. Not bad for first sea trials!

6801 Sea Trials, January 2019, La Grande-Motte, France

The launch of a new model is a nail-biting time for yacht builders, designers, and owners, no matter how careful they’ve been with the conceptual design. The first question on everybody’s lips has always been ‘Will she float on her marks?’ and in high-performance yachts, there’s a second question which is equally important, ’Can she match her polars?’

There’s a huge amount riding on whether the boat meets or misses those vital statistics generated by VPP. And for Gunboat’s design and build team, the claim we made before the first boat was even built – to deliver a performance package that would be almost fully optimized when it left the factory – was about to be put to the test. Not only that, but Condor’s polars had been calculated by VPLP, whose performance prediction program is famously accurate and notoriously hard to beat.

During that first sail in January, on an untuned boat straight out of the shed, loaded with amenities and optional extras, we saw the first proof that the Gunboat 68 delivers the power and pace we set out for. In subsequent sea trials and the trans-Atlantic delivery, Condor matched her polars convincingly on all points of sail, in a wide range of conditions from just a few knots of wind to more than 30 knots true. Stéphane Renard, Gunboat Head of Design and Engineering, explains that “achieving that boils down to a series of tightly managed, interconnected design loops between the Gunboat build team and external partners – not just naval architects but rigging experts, sailmakers, and others – whose specialist knowledge was invited into the conceptual design process from an early stage.”

The Gunboat team together with Loïck Peyron, sea trialing the first Gunboat 68, CONDOR, in February of 2019.

“CONDOR’s all-up displacement weight was precisely on target, which was crucial in enabling her to match her design polars. Boatbuilders might not want to talk about it, but it’s rare for the first yacht in a series to hit her target weight – and if significantly heavier, she would have been likely to fall short of the VPP predictions. Without a doubt the results achieved with 6801 are satisfying, and at the same time we’re continuing to spiral additional advantages we find back into production.” – William Jelbert, Gunboat COO

POWERFUL, VERSATILE SAIL PLANS

Video footage of Condor blasting along at more than 20 knots might be grabbing the headlines, but the most remarkable thing about the Gunboat 68’s design is the versatility of her platform – including the ability to accommodate different sail plans. From the beginning, hand in hand with the design of the two different rig packages (Regatta and Performance Cruising), we optimized the platform not only to maximize the amount of sail area that she can potentially carry but also to allow owners the broadest possible range of options. When they come to pick their sailmaker and make key decisions about their sails, they can choose to put the cursor exactly where they want it to suit their program – race or cruise, or anywhere in between.

The sail plan design process began with a few fundamental decisions. Furthermore,  sail plan optimizations were introduced at stages when engineers and designers could still accommodate them.

Vital to safety, on a cruising yacht with such a powerful rig, controlling sail power, and having the ability to quickly and easily reduce sail area is just as important as having it. We decided to offer three reefs in the mainsail in the standard Cruising Rig package  and four reefs with the Regatta Rig.  For the same reason, but also to enable the boat to realize her full performance potential when desired, we designed a custom mainsheet traveler system mounted on the aft beam, making it as long as possible to give the most responsive and precise control of the mainsail. The traveler was established as a priority before the rest of the aft beam plan was completed.

Double-reefed main during windy sea trial conditions. Traveler positioned on the aft beam.

Likewise, from the early stages, we evaluated how to increase the sail area where it matters most. As a result, the martingales were lowered through the crossbeam in order to get the J1 foot lower, adding power you can press on, rather than sail area up high which would compromise righting moment.

Taking advantage of another opportunity for gains, upwind performance and pointing ability also received a great deal of expert attention and a few laps around the design loop. For optimum performance upwind in light airs, we designed the Gunboat 68 to be able to carry a large, overlapping headsail (or J0) – and gave priority to the best sheeting points. Creating a sheeting point for it on the coachroof would have required complex supporting structures built into the super-lightweight carbon cabin top, adding a lot of extra weight and complexity. A better option was running the sheet to the aft beam…but the cabin top was in the way. So together with VPLP and the exterior designers, we changed the bimini roof design (because the deck plug wasn’t completed yet!) to allow this sheet to pass.

Overlapping fractional code 0 (FRO/J0) sheeted to the aft beam.

For upwind work in stronger winds, we planned for a self-tacking jib, a feature already well-established in Gunboat world. Nothing beats the convenience, efficiency, and agility, especially when short-tacking up a narrow channel or going through a reef pass. So we locked in the plan for a solent that would live on a curved track, and later configured the deck gear around it.

J3 (Staysail) on the self-tacker

J2 (Solent) on the self-tacker

Off the wind, the asymmetric spinnakers delivering maximum power are of course flown from the furthest extremities of the boat – the front end of the longeron, the masthead and the far ends of the aft quarters – and we wanted to provide two trimming options that would come standard with the boat. The spinnaker sheets can be led to winches in both the forward and aft cockpits.

Once key decisions were made, VPLP drew up the conceptual sail plans for the two rigs, ensuring that the balance, performance, and safety parameters met our targets.

SAILMAKERS IN THE LOOP

Sail design and technology have progressed enormously in the last 15 years. We’ve gone from pinhead mainsails made from panels of laminate, sewn and stuck together, to square-topped mains that are molded from a single sheet of composite material into precisely the optimal shape, which is determined by CFD software that can accurately simulate all possible permutations of sea state, yacht motion and wind conditions. The sailmaker’s art, as we used to call it, has become a complex and specialized branch of engineering. The evolution has been driven by the grand prix racing world with a remarkably fast trickle-down to mainstream racing and high- performance cruising.

Running and standing rigging have also transformed. Stiffer and stronger, effectively zero-stretch materials such as carbon, PBO, Kevlar, and Dyneema have pushed equipment suppliers to build stronger winches, tracks, and blocks. Boatbuilders, in turn, have to rethink how deck hardware and other equipment is attached and supported. Everything upstream is now zero stretch, which means pure power transfer to the boat – and enormous shock loads, which the boat’s structures must be designed to handle.

One thing that has remained constant throughout this rapid evolution of rigs and sails is the consistent innovation of North Sails, one of the world’s most prolific and technologically advanced high-performance sailmakers. Gunboat 68 owners are of course free to select any brand of sails and we’ll collaborate closely with their chosen sailmaker. That said, with the first two 68 owners both having chosen North Sails, we had the opportunity to incorporate North’s vast experience and technical expertise into the sail plan design loops – together with VPLP’s Xavier Guilbaud, leading rigging experts Nick Black (of Rigging Projects) and Torbjörn Linderson (representing Hall Spars).

North Sails on Gunboat 68 CONDOR. Scott Gray of Rigging Projects checks the rig and sails during sea trials

“About two years ago we got involved, and working with the design team from the beginning was pretty unique,” says JB Braun, North Sails Director of Design and Engineering. “Designs were based on a collaborative effort, tools were well thought out. We effectively maxed out this project on all technical optimizations…sail plan, mast position, sail sizes, and especially in designing the ideal J0 (aka FR0 aka overlapping Code 0) – overcoming where to sheet it, with cabin top slopes to specifically accommodate that sail. We were excited about the J0 because with multis, the challenge is the light to medium transition zone right before full power, and we put a lot of design work into improving this capability. Now is the fun part, to take  what we engineered out on the water!”

Sail plan view of the J0 and full-hoist main. Flying sail shapes in 12 knots of true wind speed and 50-degree true wind angle. Design image by North Sails.

Drone view looking down. Flying sail shapes in 12 knots of true wind speed and 50-degree true wind angle. Design image by North Sails.

OWNERS IN CONTROL

At the heart of it all, the sail design process was driven by the owners’ performance goals and cruising programs.

“The owners were deeply involved; talking with us about everything from how they want to use the boat and where they will be going, to reviewing sail product features and communicating their preferences.” North Sail’s Jack Slattery has worked closely as the sail expert with other Gunboats and joined the 68 design loop early on. “We had a real understanding from the owner and worked with Gunboat to match these intentions with the final product.”

For 6801 CONDOR it was all about maximizing performance while maintaining longevity. She has a suit of seven sails (five Carbon sails including the Main, J3, J2, J1, J0 plus the A3 and A2) that will get the most out of any sailing conditions; ready to race against the best or dial it down a notch and enjoy the scenery.

For 6802 DASH, the top priority was optimizing the sails and rig for long-distance cruising. Designed for ease of handling and engineered to be as low-maintenance as possible, all headsails are on furlers, with slightly softened corners that are more manageable and forgiving shorthanded (whereas on race sails the corners would be a little more rigid). There are two fewer sails on board, five in total – four Carbon/Dyneema sails (the Main, J3, J2, J0) and the A3. The headsails are designed for a wider wind range, so they’re set up to do fewer sail changes and have more space in their sail lockers for extra cruising kit. (For example, in upwind mode, Gunboat 6802’s  J0 can be carried to 14kts, vs. on 6801 they would take the option to step down to the  J1 in 8-10kts.)

“It’s validating to see how the first two Gunboat 68 owners have chosen to go in different directions with their sail wardrobes, to suit their own sailing plans,” says Gunboat Managing Partner Benoit Lebizay. “It highlights the importance of the decision we made right at the beginning of the Gunboat 68 design process, to make the boat’s platform as versatile as possible.”

SAILING REPORTS

Gunboat 68 CONDOR left the nest in March 2019, destination St. Maarten via Lanzarote. Straight out of factory sea trials, this crossing would be the first extended test and also the first good opportunity to sail in mid-range conditions. (For the most part, sea trials in LGM presented either very light or very strong breeze!)

We were thrilled to see Scotty Bradford on board CONDOR, experienced Gunboat captain (ELVIS) and one of the industry’s best at making boats go fast, so for the same reasons it was gratifying to receive this feedback:

“The 68 is an incredibly incredible boat. This thing is awesome. I joined for the first few days in La Grande-Motte and sailed to Cartagena. We had hard  running conditions going out of the Med, big steep seas, short and sharp…the boat just takes off. I noticed the way the boat handled these conditions, and there was not a creak, groan or noise – and was particularly impressed with  the boat structurally, the lateral stiffness. Clean bows, no deceleration from wave to wave…we were seeing 24-25 kts.”

Jeff Feehan, Professional Sailor who joined CONDOR for the full delivery, reported on the Transatlantic crossing from Lanzarote to St Maarten:

“We departed Arrecife Lanzarote at 11:35 April 1st, motoring/motor-sailing for the first 26 hours. We dropped anchor outside Simpson Bay Bridge, St Martin at about 14:00 on April 13th. The distance sailed was 3351 NM – having taken the classic southerly route, passing reasonably close to the 20N 30W benchmark, sailing a bit south of our eventual destination in order to stay in the pressure.  (The shorter, “northerly” route was not an option because  troughs associated with low-pressure systems in the North Atlantic caused the wind to be extremely light.) Our max speed exceeded 30kts a couple of times, and the max 24 hr run was 328 nm.”

“The trip was downwind – it was a long starboard – but we were inside the gybing angles nearly the whole time; so sailing deep, VMG sailing, not reaching,  not sailing hot or fast angles, and gybing considerably less in delivery mode than we might have had this been a race. Winds averaged mid-teens – typical days averaged 14-17kts for the trip. Throughout the different wind angles, the boards were also an essential tool to power or depower the boat, a control factor we played with relative to comfort, safety, anticipated changes in the conditions, watches/number of crew members actively sailing, etc.”

“The main goal was to deliver the boat safely, without breaking anything, but despite holding back, I think the 68 is a very fast boat. What amazed me is how easy the speed comes, and how solid and in-control the boat feels at speed. I was really impressed by how the bows ride high down the waves, mostly staying dry and only rarely sticking in at the bottom. Even then they pop out quickly – there is little or no sense of slowing down from  it, the boat just keeps going!”

We’ll leave it at that for now, content to let the boat and her sailors speak for themselves – but there will be much more to come as Gunboat 68s begin to clock miles on a whole range of blue water adventures!

Find out more about the Gunboat 68 and read the rest of the article series here. View the Gunboat 68 sailing and interior video below.

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OUTSTRIPPING THE WIND – GUNBOAT 68
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