Glass is incredibly tough—in some cases tougher than most metals but much more malleable, making it a strong and versatile structural material both on land and at sea. Yacht designers quickly followed the lead of architects and started innovating with glass to project their visionary outlook on stunning ocean vistas with unprecedented design forms.


A wise man once said that the best interior design on a superyacht is the exterior scenery. But conventional windows and portholes offered only a tiny glimpse of the outside world because glass represented the weakest part of the hull and superstructure. More recently, advances in glass technology have led to the introduction of much bigger windows that are built into the structure of yachts. Glass can be laminated, chemically toughened, curved into weird and wonderful shapes and treated to block UV and IR light. Designers and shipyards now have the means to blur the barrier between inside and outside by introducing more light and visibility than ever before. And the results can be breathtaking.

An early pioneer in the innovative use of glass on yachts was designer Martin Francis, who came up with the idea for the bug-eyed windows on Eco (later Katana and Enigma). Inspired by the curved windshields of Parisian buses, the windows represented a massive experiment in 1990. A decade later, Espen Øino introduced an overhanging glass conservatory aboard Skat, the military inspired 71m (233ft) motor yacht. When she was delivered in 2002, the extensive glazing was a revelation that made even the largest traditional yacht windows look small. Philippe Briand later paid unwitting homage to Eco with his curved windows aboard 50m (164ft) Exuma, the first Vitruvius explorer launched in 2010.

Many yards and designers have been pushing the boundaries with design concept exercises; now more than ever some of these futuristic ideas have already been put into practice: Hampshire II and Savannah, for example, both have underwater viewing ports built into their hulls (134m/440ft motor yacht Serene features a similar observation lounge known as the Nemo room). Taking the concept one step further, one yard is now said to be looking into glass-bottomed beach clubs and even a cylindrical glass elevator that extends below the hull.

The culmination of much of this research and development to date was the creation of Venus, the 78m (256ft) motor yacht designed by Philippe Starck. Remarkably, glass comprises over 30 per cent of the yacht’s surface area. The shipyard brought in Eckersley O’Callaghan, a firm of specialists that consults for Apple on the use of glass in its iconic worldwide retail stores, to advise on the enormous windows of up to 24sq m (258sq ft). The classification societies responsible for ensuring safety at sea are generally sceptical about large areas of glass on yachts, so the yacht builder tested the structural integrity of the windows at four times their normal loading.

While full-height glass windows on main deck are virtually de rigueur on today’s superyachts, extending the same to the upper deck presents technical challenges. The 72m (236ft) motor yacht Stella Maris presented a massive engineering challenge with her huge windows. In addition to the sheer weight, such large areas of glazing can transmit unwanted structural noise and vibration. To ensure quiet and comfortable cruising, the shipyard engaged a team of sound insulation experts to analyze all the potential sources of vibration and vary the type, size and thickness of glass according to its location.

The growing use of structural glass is not just confined to the exterior windows: open-plan interiors also benefit from the opportunity to increase natural light and reduce the need for solid walls and partitions. Dominating the main foyer aboard 60m (197ft) motor yacht Vive la Vie, for example, is a spectacular series of glass bridges suspended in a mesh of woven stainless steel leading from the lobby to the main staircase and glass elevator.

The trend for ever larger windows brings with it associated issues: they may improve the view, but in hot climates too much sunlight can be uncomfortable and damage interior finishes and fabrics. Curtains, blinds and sheers have been the traditional means to block excessive light and heat and provide privacy, but these necessarily shut out the seascape— the whole reason for having larger windows in the first place.

This is as relevant for sailing yachts as it is for motor yachts. Sybaris, the 70m (230ft) ketch launched in 2016, features a dramatic titanium and glass stairwell running from the lower deck to the fly deck. The laminated glass panels alone weigh over 600kg each, requiring reinforced beams to support the structure.

The trend for ever larger windows brings with it associated issues: they may improve the view, but in hot climates too much sunlight can be uncomfortable and damage interior finishes and fabrics. Curtains, blinds and sheers have been the traditional means to block excessive light and heat and provide privacy, but these necessarily shut out the seascape— the whole reason for having larger windows in the first place.

“Switchable” glass is one solution. The technology is well established and utilizes a liquid crystal film sandwiched between two panes of glass. When an electric current is passed through the film, the crystals change their alignment, turning the glass from opaque to clear and vice-versa. The limitation is that there are just two shades: clear or opaque. A more refined technology relies on microscopic light-absorbing particles that can be “tuned” to precisely control the amount of light or glare passing through the windows, blocking UV light and heat and reducing the need for air conditioning. The technology allows the glass to vary in transparency from slightly opaque to full blackout within seconds at the touch of a button.

Other researchers are looking into a type of smart glass based on micro-electromechanical systems. The glass contains micro-blinds of tiny stressed metallic foils that curl up or roll down when actuated by electrical impulses. The technology is attracting potential investors from the aerospace and automotive sectors, but has equal relevance for yacht builders.

Much of the ongoing innovation in glass technology is associated with providing greater strength, clarity, noise reduction and safety. One of the newest products is a type of chemically toughened glass that has had its atomic structure reconfigured to make it stronger and tougher, which means it can be used in thinner and lighter layers but with the same strength and scratch-resistance as regular toughened glass. It is widely used for the touch screens of smartphones, but its potential in structural applications is endless. Applied to a transparent acrylic core, for example, it provides a lightweight material designed to absorb energy rather than resist it.

What the future holds for glass on superyachts will depend to some extent on how quickly the current regulations can adapt to the rapid developments in glass technology. Certainly, expectations have already moved on. A new generation of owners fully expects the kind of maximum exposure to the marine world that only glass—and lots of it—can provide.


This article originally appeared in The Superyacht Book – an insider look into some of the most luxurious floating residences. Get your copy here.

Tony Harris
Tony Harris
Along with editing The Superyacht Book, Tony Harris spent a decade as publisher and chief executive officer of Boat International magazine.