Sea Eagle II: One of the world’s finest superyachts

Stunning images of the 81m schooner Sea Eagle II in French Polynesia are a rare chance to see one of the world’s most magnificent superyachts in full flight. Toby Hodges finds out more from the team behind the design

It’s very rare to see quite such a large vessel, the world’s largest aluminium sailing yacht in this case, truly in its element: sailing full bore in an idyllic location. To us sailing fans, it’s the equivalent of a birdwatcher photographing an exceptional species of finch, kingfisher or indeed eagle. With regards to Sea Eagle II, however, these images really do make you re-evaluate your impressions of scale.

We’ve talked in detail about this superyacht before, when it was just a vision, a project in build. But these pictures, showing it in full flight, help bring a long list of impressive technical statistics to life.

While there are many big yachts, there are very few sailing yachts as large as this – officially eight, but of those considered proper sail-powered rather than sail-assisted yachts, arguably only three. And certainly very few we’ve seen that can sail like this: seemingly with relative ease, control, power and grace.

The extensive photoshoot in French Polynesia shows Sea Eagle II really shifting under its own easily furled canvas. This should come as no surprise to anyone familiar with Dykstra Naval Architects. Look at the spray flying off the towering stemhead – this is no sailing motoryacht. From bow-on you can see the hull is comparatively very slender, with purposeful chines and a flare to the topsides aft. The waterline is fully extended as the sections transition from a rounded U-shape bilge forward to a flat run aft.

Long waterlines together with a modern, beamy aft shape helps create massive volume, powerful performance and low heeling speed. Photo: Tim McKenna

Combine this with the long glass deckhouse and it reminds of a modern explorer yacht or a naval craft. Its hull lines are strikingly efficient, purposeful even. Her 6m draught aside, you get the impression there is nowhere Sea Eagle II can’t soar to. That it has already completed a circumnavigation and sailed 45,000 miles in its first three years is less surprising when you consider just how long legged it is – indeed the crew and designers have reported sustained passagemaking speeds of over 20 knots.

But why the look, why that sailplan, and how did it get from concept to sailing in Pacific islands?

A classic start

The initial brief was actually for a more classical yacht, similar to the 90m schooner Athena that Royal Huisman built for Jim Clark in 2004, before the owner realised he’d prefer the benefits that come with a more modern shape with straight lines. This allowed for a much longer waterline and beamy transom for more stability, volume and comfort at less heel.

Passagemaking performance aboard a practical and safe yacht to manage easily was the target. Sea Eagle II was commissioned by an ageing owner who wanted a large, stable and easily driven yacht – which is why it ended up being twice the length and three times the volume and sail area of the previous Sea Eagle, a 43m yacht which launched from Huisman in 2015.

owerful schooner sailplan with heavily roached equal sized mains. The upwind sail area alone is equivalent in size to five basketball courts. Photo: Tim McKenna

The modern look came from Dykstra’s Erik Wassen, lead naval architect for the project, who I caught up with to discuss how the design transpired and if it has fulfilled its brief. Where a classic yacht “has lots of details to give it life – I thought a round bilge boat with no detail on it is just incredibly dull,” he replies candidly. This helps explain the yacht’s prominent chine, “single aft, turning into a double chine forward, to give it detail,” while in the transom the topsides are inverted, and have some negative camber. “That’s what your eye picks up – it emphasises that masculine look.”

As well as the aesthetic trickery, it’s a shape that works from a naval architecture point of view too: “the knuckle gave me more beam in the forward end of the boat where we have the foremast. The chainplates can be separated more without having too much flare in the boat.”

To manage this canvas, 34 winches can all be pushbutton controlled from the helm stations. Photo: Tim McKenna

Sea Eagle II’s striking styling is set off by the long deckhouse with its straight glass windows, which cements an explorer look. The UK’s Mark Whitely, who designed the interior, drew this profile. “We went with that and explored it further to sink the bridge half into the superstructure to keep the overall height limited,” Wassen explains.

A schooner rig featuring three carbon masts with furling booms was deemed the most effective way to give Sea Eagle II the most manageable sail power at the Panamax limit (61m). Dynarigs, as used on the Dykstra projects Maltese Falcon and Black Pearl, were not appropriate for an owner who preferred more classic styles. And while Wassen says they did consider square-top sails, the additional complication was considered too high at the time (around 2017). Instead, the three heavily roached mains have proven to provide ample sail area.

Royal Huisman’s sister company Rondal built the three equal size high modulus carbon masts, as well as the furling booms, captive and drum winches, while Carbo-Link supplied the carbon standing rigging.

Note the size of the crew to get a scale of the aft deck and beam. Photo: Tim McKenna

Straightforward sailing

The beauty of the sailplan is that it can set so much canvas on easily managed push button furlers. The 34 winches are all interfaced and controlled by Rondal’s integrated sail handling system. The Stratis-built fore, main and mizzen sails can raise simultaneously thanks to plenty of hydraulic juice powered by twin 120kW gensets and power take-offs on the main engines.

When you include the staysails that can set off each mast and the yankee, there are seven furling sails from Doyle, totalling around 3,500m2. And that’s without a kite (which the new owners are looking into adding, with rumours of future racing events such as the RORC Caribbean 600).

“Tacking is very straightforward,” reported Royal Huisman’s commissioning skipper: “the mains mostly look after themselves with only minor adjustments.

“Gybing naturally takes a little more orchestration, as on any large yacht. But it is still a smooth and safe process.”

Side decks you could fit a skittle alley on, yet protected by high bulwarks. Photo: Tim McKenna

The yankee sheet has the most load, but even that’s on an 18-tonne pull winch, which is reasonably common in large yachts. To depower the sailplan, the crew typically reef from the mizzen first, with the reefs all on halyard locks.

In terms of performance, this is a mile-munching machine. “In a good breeze, on a beam reach, with reefed sails, it does 20 knots comfortably without pushing it,” Wassen reports. This is confirmed by Huisman’s commissioning skipper who reported high boat speeds that are easy to maintain: “We comfortably recorded 22 knots in moderate wind conditions. In fact, at 16-18 knots boat speed, I found myself regularly checking the B&G speed displays for confirmation because the motion is so relaxed. Sailing fast with just a gentle heel [typically max 10-15°], she feels very safe.”

Wassen stresses it’s never had a race crew aboard, so has never been pushed. “We know the boat has been doing sustainable 20 knot+ deliveries… so I think the performance polars we made are doable.”

Palatial space at anchor. Transom hinges to create a full beach terrace. Lazarette includes a crane for the 8m guest tender plus toy space. Photo: Tim McKenna

He attributes the commendable performance to the long waterlines, where buttocks slowly rise to a transom that is only just clear of the water. But credit must go equally to the stiff and strong build. Typically yachts of this scale are built in steel, which results in a much heavier structure. Royal Huisman are masters in large aluminium craft and this, its largest to date, helped them further the technology – learnings which have continued to progress with the launch of its recent full performance yacht Nilaya and the colossal 85m sloop in build.

The complexity of Sea Eagle II’s build, and its four years in engineering and construction, cannot be understated. The goal was to find the right balance between strength and flex, the former to ensure the necessary longitudinal strength and rigidity, the latter to absorb the dynamic shock loads from waves.

bridge fit for a ship for fully protected watchkeeping. Photo: Tim McKenna

Glass doesn’t bend

An example of such a construction challenge lay with how to mount such a long, rigid deckhouse structure, which comprises so much laminated glass, onto a more flexible aluminium hull. “When we were doing the FEM [finite element method] analysis, we noticed that the glass mullions would be picking up a lot of the load,” Wassen explains: “the deck is participating in the overall structure and a boat with this beam will deflect and bend in waves.”

As glass won’t flex, the build team needed to include some tolerance between the roof and mullions. Aerospace specialists developed an adhesive specially for this project, using it to bond the forward section of the deckhouse to create 2cm of flex.

The al fresco dining area beneath the aft overhang, with grand stairs each side to the flybridge. Photo: Tim McKenna

This long run of glass is central to the overall aesthetic, something Mark Whitely elaborates on: “The essence of the yacht’s appeal is illustrated by long, uninterrupted lines of glass, a subtle sweep of superstructure and a blister to enclose the semi-raised bridge.

“The proportions and low profile were driven by the owner’s request to have a continuous floor from the exterior dining space, right through the large main saloon to the forward dining saloon, with no steps.” The photos confirm side decks you could bowl down, and fore and aft decks clear enough for racket sports.

The formal dining and leisure area at the forward end of the deckhouse. The curved, forward windscreen gives a panoramic outlook. Photo: Tim McKenna

Elsewhere on deck there are foldout boarding platforms on both sides. Outside and inside worlds are separated by flush sliding glass doors which disappear into their own garages, while steps each side of the dining area lead to the expansive flybridge to offer another full deck of entertaining space and an ideal vantage point to helm from.

Another prime feature of Sea Eagle II’s design is the full bridge nestled between flybridge helm station and the main deckhouse, from which it can be commanded in heavy weather. Deciding at which of the many long tables to sit or relax at would seemingly be the only headache for owners and guests. Whether alfresco on the aft deck, inside/outside bar seating, the decksaloon or a formal dining and leisure area forward with 180° windscreen views, all are on the same level.

The main accommodation is for 12 guests, while forward of the foremast is a separate low profile entrance for the 14 crew to reach their quarters. The stowage space for toys is formidable, complete with cranes to launch all with minimal fuss.

A modern silhouette of purposeful performance, with lengthy waterlines and an extended deckhouse. Hull chines are mirrored on the booms. Photo: Tim McKenna

However, while it offers palatial comfort at anchor, this is a yacht that clearly comes alive under sail. In summary, these photos prove what the jury at the Design & Innovation Awards 2021 said when awarding Sea Eagle II with the ‘Best Naval Architecture Sailing Yachts’ award. “She is not just a large cruising yacht with global capability but a beautiful boat that sails well.”

Sea Eagle specifications

LOA: 81m 266ft
Beam: 12m 40ft
Draught: 6m 20ft
Hull speed: 22 knots
Main engines: 2x 1,081kW
Generators: 2x 120kW
Air draught: 61m 201ft
Sail area: 2,580m2 27,770ft2 upwind / 3,552m2 38,233ft2 downwind
Design: Dykstra Naval Architects + Mark Whiteley Design

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