Xucia is Mini 6.50 #1081, a radical Sam Manuad foiling mini and hydrofoiling iteration of the popular single-handed class. Rupert Holmes looks at the accelerating pace of change in the Mini 6.50s

The past few years have seen an explosion of activity in the Mini 6.50 class, with qualifying races for the iconic Mini Transat race oversubscribed by up to 100% and two-year waiting lists for new Series-built boats.

Yet the front of the fleet is no longer an economic place to go racing. Typical fully equipped prices for new Series builds are around €150,000, while the bill for new one-off Protos is well over double that figure, reflecting the costs of full carbon one-off boats that incorporate build knowledge gained from America’s Cup campaigns, plus in some cases the enormous cost of foils.

Innovation hotbed

Historically the class has been a hotbed of innovation. It’s here that twin rudder designs and canting keels were first refined and proven to be reliable, even if some of the latter initially had problems when scaled up to much larger yachts. However, for the past few years almost all new development has been in the lower-powered Series fleet, where scow bows have been the norm for several years.

In contrast to the IMOCA 60 fleet, foiling designs have so far been slow to take off, but that’s changing rapidly. This year sees nine new Proto boats set to be launched, many of which push the boundaries of yacht design.

Carlos Manera’s Xucia is designed to be a low-riding foiler with the transom just maintaining contact with the water. Photo: James Tomlinson

Unlike foiling IMOCA 60s, Minis are allowed T-foils on their rudders, which opens up the prospect for a full flying boat. This was the approach taken by the early foiling Minis, including Seair’s David Raison-designed #747 in 2017 – the first-ever flying offshore monohull – and the Verdier-designed Pogo Foiler that launched in 2019.

When I visited Lorient-based Seair back in 2018 development engineer Hugo Feydit told me they were seeing speed advantages of up to 30% compared to the Archimedes Protos of the time. This boat was originally intended as a proof of concept, so it was judged imprudent to build both foils at the outset, in case testing showed a different foil shape was needed and as a result it could only foil on starboard tack. Funding was not forthcoming to build the other foil, which means the boat never raced so direct comparisons with the fleet could not be made.

However, the Pogo Foiler is a different matter. Although Covid forced a break in his early racing schedule, Tanguy Bouroullec, skipper of the first boat, produced some stunning results in 2021, winning the first two races of the season. However, he’s yet to convert the boat’s obvious potential into a Mini Transat win. Although his is a full-flying boat, Bouroullec is very conscious of avoiding heavy splashdowns and when I sailed with him a couple of years ago we kept the leeward corner of the transom just in contact with the water. Nevertheless, it was an exhilarating ride, with boat speed hovering around 17-18 knots for extended periods in 18-20 knots of true wind.

With retracted C-foils. Photo: James Tomlinson

Low riding option

One of the most recent of the new boats is Xucia, sail #1081, a Sam Manuard design for young Spanish skipper Carlos Manera that’s been professionally built at the Sinergia Racing Group’s yard in Cartagena. Manera says he and Manuard shared a similar vision and philosophy for a low-riding foiling boat with retractable C-foils that would offer a significant speed boost in medium and strong winds, without being at a disadvantage in light airs.

This is notably a different philosophy to that of another new Manuard design, Caroline Boule’s #1067 Nicomatic (aka Bill), which is a full flying boat. It was launched last year, but foils weren’t fitted until autumn 2022, so we can’t infer anything from race results to date. A full-on flying Mini is arguably still a risky strategy, but it’s one that Boule, a Franco-Polish nuclear engineer with a background in team racing and foiling Moths, is well placed to capitalise on.

In the past Mini sailors were renowned for getting their hands dirty building their boats, but the popularity of series designs means that’s far less common today. Instead the focus is on maximising time afloat, honing skills and gathering data. Bucking the trend, both Carlos and his sister, Elena, helped hands-on with the build of Xucia, spending six months at the yard. “Some bulkheads and many of the smaller parts were done only by me,” he says, “and we have been learning from the professional team at the yard all the time.”

A clearer view of the C-Foils deployed. Photo: James Tomlinson

Although the boat is a one-off, all tooling was made using CNC moulds – believed to be the first time for a Proto Mini 6.50. “We used the same technology as INEOS Britannia and other America’s Cup teams,” says Manera. Close attention to detail during the build means the boat came out a little lighter than expected, despite the additional weight of the foils and associated structural reinforcement compared to a conventional design.

Clear vision

Manera, who completed the last Mini Transat in an 11-year-old Series boat, started this project with a crystal clear vision of what he believes to be necessary for such a tiny foiling boat to perform reliably in an oceanic race. His overriding priority is avoiding the big loss of speed, and decelerations that can be damaging to both boat and skipper, when a boat suddenly drops off the foils. Instead, his boat is not intended to fly high and the transom will always be in touch with the water. The foils therefore help increase righting moment and reduce wetted surface area to an absolute minimum.

“The main idea was not to fly,” he told me. “Sam Manuard originally proposed the same design as Caroline’s boat to me, but I turned it down because I don’t want to fly. The reality at the moment is we are too far away from being able to cross big waves in hard conditions and stay flying. Maybe it can be achieved in the future, but I don’t believe it’s possible right now.

Gooseneck, boom and mainsail are all designed to boost end-plate effect to maximise the power that can be derived from the bottom of the sail. Photo: James Tomlinson

“The human factor means we need to be relaxed and need to have constant good mental strength. When you are full flying, it’s difficult to rest, it’s really difficult to keep the trim right, and it’s really stressful for you and the boat.”

Xucia therefore has relatively small retractable C-foils that boost righting moment, while producing a bows up attitude. This reduces the propensity for the boat to nose-dive into a wave, giving a smoother ride, while the extreme scow bow shape offers a lot of reserve buoyancy if the boat does splash down.

Manera says this means good control of the boat is maintained all the time: “You are not flying, so the autopilot can manage and you can rest, because the boat doesn’t smash into waves, it just passes over them.”

The now-standard scow bow shape provides both form stability and reserve buoyancy forward. Photo: James Tomlinson

Getting the bows well up also reduces wetted surface area by up to 80%, which creates a massive speed boost compared to conventional boats. When the C-foils aren’t needed in light airs they can be retracted clear of the water – a big gain compared to the big foils of flying boats whose drag can never be eliminated.

High averages

I first spoke to Manera four weeks after the boat was launched, during which time he’d been training in mostly light to moderate winds of up to 20 knots. “The feel of the boat is really, really good,” he says, “and it has the behaviour we wanted from the design, with a very soft ride on the foils and no big bursts of speed. But what’s really interesting is the speed is always very constant. That was the main goal – to maximise the average speed, not peak speeds.”

He also reports the boat is “really balanced and smooth” and that the pilot – currently an NKE GyroPilot 3 while waiting for the HD version to be available – works really well.

In lighter airs the C-foil (left) can be retracted, to sail with canting keel and twin daggerboards. Photo: James Tomlinson

Key priorities before the first Classe Mini races this season are to continue testing to build a full set of data that will identify the fastest mode in all conditions. Despite their diminutive size these are complex boats, with a myriad of sail plan permutations and many options for fine tuning the foil settings, so this is far from a trivial task.

Accurate instrument calibration, for instance, is critical for a good pilot response and to build the data needed for sail selection. Given the complexities of measuring variables such as upwash angles at the top of the rig over a full range of wind speeds and angles, this takes a huge amount of effort at the highest levels of racing. So for most, perfect calibration is a distant goal you’re always working towards.

It’s even more complex for foiling vessels, whose boat speed sensor – one of the four critical components needed to calculate true wind speeds and angles – regularly lifts out of the water. This whole area is one that Feydit told me was “a huge challenge that required a vast amount of work” for the Seair boat.

Slick twin-winch layout saves weight and borrows cockpit ideas from IMOCAs and Class 40s. Photo: James Tomlinson

Manera has only limited time to achieve this before the first races in the Atlantic season, starting with the 250-mile two-handed Plastimo Lorient Mini race, in which he will compete with Elena as co-skipper, just after this issue goes to press. While others are struggling to get a place on this autumn’s Mini Transat (starting September) Manera has already secured one of three spots reserved for boats measured for the first time during the year of the race.

Xucia is not the only entry with C-foils in this year’s Mini Transat. Geoffrey Morel’s #945 Tartine, a Marc Lombard design from 2018, was designed at the outset to be retrofitted with foils. However neither of her first two skippers, Axel Tréhin and Fabio Muzzolini – who finished 2nd in the last Mini Transat, took the plunge. The boat’s new C-foils have a very large chord measurement and again provide plenty of stability while also lifting the hull just above the water.

Given the two different schools of thought among foiling boats – full flying or low-riding – plus five new non-foiling Protos from the same mould as the winner of the last two Mini Transats, it will be interesting to compare their respective performance both in the shorter races this year and in the Mini Transat. The history of the Mini class tells us the outcome of the battle between the different styles of foiling boats and the latest Archimedes designs will have big ramifications for future developments in the wider offshore racing world.

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