Two Taikoo Place, Hong Kong. Image: Eckersley O’Callaghan

The market position of glass has been transformed over the past 15 years. Looking at the yachting market today, you’ll find that ‘strengthens your connection to the ocean’ has become one of the buzz phrases plastered across every pamphlet and brochure … and for good reason. The days of behemoth, for-tress-like yachts built for secrecy seem to be fading, at least in part. In their place, we’re seeing a wave of designs that embrace the true essence of yachting, which is an intimacy with – and love for – the sea.

This transparent revolution is continuing to shatter preconceptions of design. Until now, ambitious glazing projects have pushed the boundaries aesthetically and structurally, with Feadship’s 78-metre Venus often being hailed as the poster child for such innovation. With input from glass engineering firm Eckersley O’Callaghan and launched in 2012 for the late Steve Jobs, Venus features an unprecedented amount of glass for its time. Windows extend the length of all main deck staterooms and an all-glass pavilion deck offers divine vistas at sea.

“Venus was a true pioneer in integrating large glass into shipbuilding at an unprecedented scale,” explains Ralf Scheuer, sales contact for marine at glass manufacturer sedak. “It set new standards for ship glazing, proving that glass can be both an architectural and functional element in yacht design. That project paved the way in the marine business for what sedak does today – pushing boundaries and delivering cutting-edge solutions.”

Since then, similar types of larger-format glass have been adopted on many projects, with owners now looking at ways to build on this and push glass designs even further. “Our expertise in oversized ship glazing – both flat and curved – allows us to redefine modern yacht design,” continues Scheuer. “We provide not only hull and superstructure glazing but also all-glass balustrades, infinity pools, portholes, and 360° panorama glazing, ensuring that these elements withstand the toughest marine conditions while enhancing both aesthetics and functionality.”

Eckersley O’Callaghan director Ian Langham explains that the design for Venus employs large-format panels measuring 10 metres in length, and owing to the firm’s collective knowledge of pushing the possibilities of glass on land with projects such as Apple Park (the corporate headquarters of Apple in California), they were able to bring a degree of lateral thinking to Venus and other superyacht projects.

Venus’ windows extend the length of all main deck staterooms and the pavilion deck is all glass

“The use of glass on superyachts has advanced considerably over the last 15 years,” says Langham. “When we started our journey, it was clear the industry was missing opportunities to use available technologies and larger glass sizing, combined with a less developed technical knowledge of designing and engineering glass as a material.”

For leading shipyards such as Sanlorenzo, leveraging the advantage of having an in-house department dedicated to design, development and engineering has enhanced its capabilities with these increasingly complex glazing projects. Sanlorenzo also collaborates with Class societies to establish the engineering foundations for new solu-tions and construction standards.

“Each project is conceived with the goal of maximising transparency and the connection with the sea, [while] always maintaining strict safety and stability standards,” says a spokesperson from Sanlorenzo. “The use of next-generation laminated structural glass and high-strength material frames allows us to push the boundaries of design without compromising the yacht’s performance, striking the perfect balance between aesthetic ambition and engineering requirements.”

This pursuit of more efficient, high-performance glazing has fundamentally changed the way yachts are designed. As our understanding of glass properties has advanced, so too has its seamless integration into hull structures, blurring the lines between solid and open spaces. A defining example of this shift is the Sanlorenzo SX88, launched in 2017, which was among the first yachts to fully embrace floor-to-ceiling windows on the main deck, setting a new standard for transparency in yacht design.

“We also see a lot of clients getting used to a certain experience with glass on land, and they want to have that on their vessels. These kinds of things contribute to a rise in demand,” says Langham. “These projects use a lot of unique glass typologies, which is one issue. There are also a select few trusted manufacturers capable of meeting these requirements. This creates a bottleneck. These firms have a maximum output and it could become increasingly hard to meet demand if something doesn’t change.”

While designers dream big, the reality is that superyacht glass presents major engineering and logistical challenges – challenges that shipyards, suppliers and Class societies are still figuring out how to solve.

Glass may provide breathtaking views but it also needs to withstand structural loads, thermal stresses and impact forces that land-based glazing never has to deal with.

“Sedak supplies flat and curved glass up to 20 metres in length, not just for architecture but also for superyachts," explains Scheuer. “We ensure that each project benefits from our expertise, assisting in smart design development and working with skilled installation teams. Precision and durability are key in maritime environments, and we take pride in delivering high-quality, bespoke glazing solutions.”

It’s a matter of the bigger the glass, the bigger the problems and, unlike buildings, yachts move and flex, further complicating design. Glass may provide breathtaking views but it also needs to withstand structural loads, thermal stresses and impact forces that land-based glazing never has to deal with.

So what’s next for glass? Firstly, as demand for more advanced glazing grows, one must wonder if the industry will meet it. Or is it approaching a breaking point? Well, despite growing fears, some of the more renowned glass specialists in the industry are up to the challenge, but there are potential headwinds that need to be addressed before we’re in the clear.

“In the last five years, we have doubled our production capacity,” explains Henning von der Thüsen, managing director of TILSE. “But what is more important is that we extended our capabilities to produce and handle larger glass panes and be able to install bigger and heavier windows to meet growing demand in the market for larger windows in more exposed positions. For these, the installation process is a lot more complicated. That’s why we needed to develop big customised glass-installation tools for recent projects.”

Other developments in glass design innovations are meant to meet demand in production methodologies. Take a doubly curved piece of glass, for example. Until recently, you had to create a mould, and every single mould needed to be custom-made to achieve the desired curvature. Thanks to advances in tempering technology, curvature can be made directly on the production line, eliminating the need for bespoke moulds. This speeds up production and opens up more possibilities for complex curvature projects.

Italian glass firm Viraver Technology has also been a key player in supporting shipyards in the growth of the yachting industry. Marco Mazzarolo, CEO of Viraver, says that to meet the growing demand the company has invested substantial sums into its production facilities and has its workforce operating at double time to meet expectations.

“We are currently operating in mul-tiple shifts to meet the growing demand. Viraver is equipped with new bending ovens, state-of-the-art clean rooms for assembly and a modern efficient chemical hardening plant,” says Mazzarolo. “In regard to the potential crisis looming ahead, we are confident in our ability to manage any unforeseen challenges promptly. We haven’t encountered any projects that have caused us concern. We’re all about being responsive so we never get stuck in bottlenecks.”

Top and middle: Viraver’s clean rooms and curved and spherical glass produced with new bending ovens.
Above: Iona Skydome (image: Simon Kennedy) and Woolbeding Glasshouse, West Sussex (image: Raquel Diniz).

There could also be lessons learned from other sectors to meet capacity requirements by expanding the procurement and supply chain to a more global platform to countries with massive capacity, such as China. Currently, the chain is naturally based in Europe, and the logistical issue of carrying large-scale glass projects intercontinental is a daunting prospect. However, it’s being done effectively in other sectors like commercial construction and cruise liners, so there’s no reason to believe the same couldn’t be applied to yachting based on distance alone.

Von der Thüsen points to fundamental constraints in glass manufacturing as one of the most significant barriers to further innovation. Glass is produced worldwide for construction, automotive and yachting applications. However, it’s made within set size limitations that cannot be easily exceeded. Due to the chemical toughening process, glass should not exceed approximately 2.7 metres by 6 metres. Pushing beyond these dimensions introduces major technical challenges, significant cost increases and complex handling requirements.

Even with shipyards adapting, the difficulty of producing large curved sheets at scale is another major constraint, and lighter stronger materials are essential for the next phase of glazing evolution. “One of the most critical aspects is the production of large sheets with complex curvatures,” adds Sanlorenzo. “Our sug-gestion as boat builders is for the glass industry to imorove lighter solutions while maintaining high standards of resistance. This will help us to keep pro-ducing high quality superyachts without compromising aesthetics.”

There’s also the issue of installation and replacement. The larger and heavier the glass, the more difficult it is to manoeuvre and, more importantly, replace. Owners may rethink oversized glazing altogether if a window can be removed only by dismantling structural elements such as staircases or fittings.

“So, of course, the reality is that the glass used on yachts isn’t the glass you’d put on any normal building projects,” says Langham. “Designing glass for yachts has many unique requirements that must be well understood, such as larger design pressures and flexing hull movements and interfaces.

“But the principles broadly remained the same, albeit the Classification society also needed to be convinced. The Classification rules have historically been developed primarily for flat glass, but for curved panels this doesn’t take full advantage of the inherent stiffness created by the geometry and the associated reduction in weight.”

“You have to understand where the load transfer and movement accommodation is. This is an area people can get wrong because they haven’t thought about the interfaces .... Steel can yield and maybe distribute the load somewhere else. The glass won’t do that.”

The issue with glass is that it’s not the most forgiving material to work with. If you get it wrong, it’s going to let you know. So even if you are pushing to meet the delivery dates required by the shipyard, there’s little room for error. It’s an incredibly daunting feat to design glass as a structural element rather than purely for an aesthetic function.

“That’s true of all our projects,” adds Langham. “You have to understand where the load transfer and movement accom-modation is. This is an area people can get wrong because they haven’t thought about the interfaces. You need to under-stand about the detailing for glass, whether that’s a glass staircase or an interface with the hull. Steel can yield and maybe distribute the load some-where else. The glass won’t do that. The hull movements you get in the ships are real. During sea trials, you can see the movements happening. It’s not like the theoretical movements you may get a lot of the time in buildings.”

Von der Thüsen agrees. TILSE is constantly developing its laminated safety glass to meet changing requirements, focusing on optical quality, durability of the laminate and low weight. “In terms of durability, it is crucial to ensure that the glass doesn’t need to be replaced at any time as this will be quite complex for large windows being part of the integral structure,” says Von der Thüsen. “As delamination is a big problem and a cause for the replacement of windows due to instability [safety issue] and visual quality, it is essential to minimise the potential risk of delamination for these glasses to ensure scalability.

“The more glass is used on board, the more important the weight of the pane becomes. Using chemically toughened glass and our special resin for laminating the panes, our compound glass guarantees the lowest possible weight while obtaining the strength required by the Classification societies.”

For shipyards like Sanlorenzo, this is a challenge they have had to meet head-on. “The glass must ensure strength, safety and thermal performance with-out compromising the rigidity of the structure,” they explain. “We’ve deve-loped advanced construction solutions, such as composite material frames and high-strength metals, to maintain structural integrity without sacrificing aesthetics.”

Another challenge in expanding glass use on yachts is balancing environmental performance, solar gain, privacy and transparency. These often conflict, particularly when incorporating complex geometries. “One of the challenges we see is how best to find the sweet spot and balance these, and these will differ from project to project,” says Langham. “Whether it be smart switchable glass that can change its qualities depending on what you require it to do through a typical day or having a curved glass with a high-performance coating too, there are many levers to pull.”

For Mazzarolo, this concept begins with design, looking at reducing thickness, aiming, weight, fuel consumption and heat transmission. “We also focus on recycling processing waste, where over 200 tons of glass are sent to recyclers for a new lease of life. And while it’s difficult to be certain, I estimate that around 40 per cent of materials can be reused in marine applications,” says Mazzarolo. “Regarding new [eco] materials that can be combined with glass, new energy solutions and new dimensions, we must remember that while technologies like solar are emerging, the time for certain glass applications may not yet be ripe.”

Sanlorenzo’s view on future inno-vations aligns with the broader industry push towards smart and sustainable materials. The idea that glass could become interactive, energy-generating or dynamic is something we’re already seeing in architectural projects – and it’s only a matter of time before it hits yachting.

Sanlorenzo says, “The integration of structural glass with smart functionalities, such as interactive surfaces that respond to touch or glass with photovoltaic properties, could not only innovate but [also]  completely revolutionise the very concept of glazing on board. This would transform windows into dynamic and multifunctional elements that enhance the on-board experience and actively contribute to the energy efficiency of the superyacht.”

Despite its challenges, glass is set to play an even more prominent role in superyacht design. As manufacturers push the limits of scale, strength and sustainability, the next generation of yacht glazing will be more intelligent, lighter and more integrated. And while application and appetite for glass have come some way, we can still learn many more lessons from the build environment. Still, with the ever-increasing interest and demand for innovation from owners and designers, perhaps our industry will be leading the way soon in what’s possible in terms of designing with glass.

“What is exciting about these [yachting] projects is realising something that hasn’t been done before,” concludes Langham. “The other part is that yachting is a breeding ground for technologies and innovation. Some owners have the means and aspirations to push things forward. The more you push the boundaries, especially in a yacht environment with high loadings, the more crucial it is to engineer every detail properly. That’s the challenge and the opportunity.”

This article first appeared in The Superyacht Report – New Build Focus. With our open-source policy, it is available to all by following this link, so read and download the latest issue and any of our previous issues in our library.

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