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Boat of the Week: With an All-Aluminum Hull, This Rule-Breaking 250-Foot Superyacht Glimpses the Future of Design

The G250 concept is not only forward-thinking in its design, but its all-aluminum hull and superstructure are breaking the rules of superyacht construction.

The G250 is a new superyacht concept built from aluminum with sustainable deck design. Courtesy Alexander McDiarmid

What do Jeff Bezos’s 417-foot sailing yacht Koru, Lürssen’s near completed 400-foot JAG and Abeking’s 388-foot Project 6507 have in common? Aside from 2023 delivery dates, the answer is steel hulls. Steel remains the material of choice for nearly all gigayacht builds, favored for its strength and rigidity.

Designer Alexander McDiarmid is moving against that conventional wisdom by arguing that when building big, aluminum is the best material. And that’s what his 260-foot concept “G250″ is all about.

Silver Yachts’ 295-foot all-aluminum Bold shows that it can be done. As does Heesen’s 267-foot Galactica (formerly Project Cosmos), albeit with a patented “backbone” to minimize flex. But it’s a small list. Since the G250 was first floated as a possible collaboration with Ghost Yachts several years ago, only five aluminum yachts over 260 feet have been built.

This G250 Superyacht Concept is a boat of the future because of its sustainable hull and all-aluminum construction.
The interior by Silvia Iraghi is more contemporary than the futuristic exterior but complements the design. Courtesy Alexander McDiarmid

“People regard aluminum as a good option for small tenders, but they don’t apply that mentality to the big boats,” McDiarmid told Robb Report. “In my opinion, if you build lighter, you build better.”

The G250 employs a hard-chine planing hull with a wave-piercing reverse bow designed by Andrew Lea of Norson Design. It’s mated to a carbon-fiber reinforced superstructure and powered by four MTU diesel engines and double Voith Linear jets to deliver a predicted top speed of 37 knots.

The helideck. Courtesy Alexander McDiarmid

“High-speed planing hulls are Andrew’s area of expertise,” says McDiarmid. “The advanced naval architecture and hybrid propulsion system sets this concept apart.”

From bow to stern, the G250 is an exercise in crossover design. It includes a shaded, sunken guest lounge on the main foredeck, which is revealed by raising a section of deck that sits on four poles. The “conversation pit” is a design trend borrowed from urban architecture, while its lift engineering is inspired by Japan’s Maglev trains, which use magnetic levitation to propel the trains forward. And in a nod to McDiarmid’s automotive design experience, a “Tom Petty pleat” runs amidships to aft, so-called in honor of the late singer whose songs were playing at the time the concept was being sketched.

“The pleat is a unique surface change that breaks up the exterior aesthetic,” he says. “You see it in supercar design a lot, but it gives the yacht a hauntingly beautiful profile.”

The G250 is a 250-foot superyacht concept of all-aluminum with a sustainable design.
A bird-of-prey-beak bow. Courtesy Alexander McDiarmid

McDiarmid’s “build lighter” mantra also extends to the number of decks. The G250 does away with the dedicated owner’s deck typically found on a yacht this size, keeping instead to a main deck, bridge deck and sundeck with jacuzzi. A large infinity pool on the main deck aft includes a waterfall that drops into a backlit water wall in the lower-deck beach club and spa.

“If an owner wants an extra deck we can certainly include it, but the yacht has better fuel economy without and is geared towards maximum efficiency,” he says.

Two 33-foot custom tenders, also featuring Tom Petty pleats, are stored in a tender garage forward. At the bow is a heliport, which is capable of supporting an AH145 helicopter. There are also accommodations for 20 crew.

The G250 superyacht concept is not only forward-thinking in its design, but its all-aluminum construction promises to break all the rules of superyacht construction.
The outdoor lounge on the upper deck. Courtesy Alexander McDiarmid

The interior design by Silvia Iraghi complements the exterior, though with a less futuristic slant. A full-beam owner’s suite on the main deck forward enjoys two drop-down balconies on either side. The suite links to the main salon via a private library and study.

Designed with customization in mind, the earthy palette swaps bold colors for textures and natural materials, such as leather and stone. Iraghi was also careful to approach the design with buildability at the fore. Following several years as an interior installation manager at Germany’s Nobiskrug shipyard, Iraghi now works as an interior project manager at refit yard MB92 alongside running her own design studio.

“I didn’t want to put forward an interior concept that has wow factor at first glance, but can’t actually be built,” she told Robb Report. “I understand the extra costs and delays that in-build modifications cause, so I always design with weight, size and durability in mind.”

This G250 Superyacht Concept is a boat of the future because of its sustainable hull and all-aluminum construction.
The main suite with very high ceilings. Courtesy Alexander McDiarmid

The concept’s customizable design extends to the flexible general arrangement, something that McDiarmid sees as a must to appeal to a new wave of younger owners. As proof, McDiarmid has again teamed up with Ghost Yachts to create an even longer aluminum concept, the all-new 344-foot GWP-345, which is an extension of G250 platform.

Featuring an even more efficient high-speed propulsion solution combined with increased levels of circularity and sustainability, the GWP-345 will “knock anything else out the water,” says McDiarmid. All that’s left is an owner willing to put his aluminum theory to the test with a new build.

Click here to see more images of the G250.

Courtesy Alexander McDiarmid

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