The Long View

Builders of boats from 30 to 300 feet LOA are adding more and bigger glass sections
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Glass House: Sunseeker’s 74 Predator has large windows on all sides and overhead, including the opening sunroof.

Glass House: Sunseeker’s 74 Predator has large windows on all sides and overhead, including the opening sunroof.

“I met with three sets of customers this week, and the message was more glass, more glass, more glass,” says Rob Parmentier, president and CEO of Marquis Yachts in Pulaski, Wisc. “Let’s be honest, people go on boats to relax, and they want access to those serene views. They want to see the sun rise, they want to see it set, they want to see the water.”

This year, Marquis teamed up with Lexus to build a 65-footer scheduled to be released in September. The LY 650 catches attention with its dramatically curved windshield and windows that make up almost the entire sides of the cabin. “Windows let the sunlight in,” says Parmentier, “but they can also make a boat really sexy looking.”

It’s apropos that Marquis’ new boat arrives via a partnership with a carmaker, because the glass revolution now sweeping through the marine industry—bringing bigger panes, in more places aboard than ever—is at least partly attributed to auto design. Carmakers have gone to bigger, more exotically curved and frameless glass in recent years, setting new customer expectations for how it is possible to feel inside a moving vehicle.

“The trend is really coming from the automotive industry,” says Mike Sturm, vice president of engineering at Taylor Made Systems in Gloversville, New York, which provides much of the marine glass produced in the United States. “People see it on their cars, and they want it on their boats, too.”

Boaters also are experiencing new levels of melded indoor-outdoor spaces in homes, further raising expectations for boatbuilders. “Clients want to feel like the outside and inside are integrated, parallel to what they have in land-based structures,” says Ewen Foster, director of design and naval architecture for Sunseeker in the United Kingdom. “Glass allows us to achieve that.”

Beyond bigger windows and windshields on boats, glass has also worked its way into new realms, including structural components, decks, hulls and even sections below the waterline. New production capabilities are letting boatbuilders use increasingly large panes of glass that weren’t even being produced in the past.

“We feel our role is to push the limits,” says Jeroen Droogsma, the innovation manager at Vripack Design in the Netherlands, which has designed large complex projects with extensive glass surfaces.

Droogsma’s team designed the 443-ft. (135-meter) Texelstroom island ferry, with huge connected glass domes on the upper deck. The multifaceted domes are bonded by rubber and elastomer fittings, and while they support themselves partly, they also require a steel frame. Vripack also designed another project on a superyacht with a glass upper deck. Droogsma says that the the framed glass panels were strong, but to protect against winds and the boat’s motion, they also needed aluminum supports. “There are often tradeoffs,” he says. “But it is all worthwhile.”

Taylor Made’s furnace is creating ever-larger windshields and other shaped panels.

Taylor Made’s furnace is creating ever-larger windshields and other shaped panels.

The How

The walls of Foster’s office are covered with architectural drawings and photos of Sunseeker yachts. Looking around the room gives him a retrospective of yacht design during the past 20 years. The biggest difference he sees between then and now is the number and size of windows, even though, he says, “The technology behind glazing hasn’t changed much.”

There are two basic types of marine glass: heat tempered and chemically tempered. They are stronger than standard glass and crumble, instead of shatter, when broken, a quality that is important for safety. What’s changed is that in recent years, suppliers have updated production equipment, allowing them to make larger sheets. In the early 2000s, boatbuilders couldn’t get glass sections bigger than roughly 7-by-4 feet, Foster says. Now, 20-by-15 feet is common, and the larger sheets can be produced at greater thicknesses. “It’s really almost unlimited,” he says.

More recently, a new type of glass has emerged. It consists of thinner layers of chemically tempered glass bonded by high-tech laminates, which add strength and reduce weight. The laminates also keep the glass together if it breaks, making it safer.

To accommodate the larger glass panes in a way that doesn’t compromise a boat’s structure, builders have developed mounting products and techniques including glues, laminates, caulks and bushings. “Instead of bolting in a frame, now we’re gluing in glass,” Parmentier says. “It’s not an easy process, and there’s a long setup. It takes time.”

But it works, and it too has helped glass take over the superstructure and move down into the hulls and onto decks in more and more boat designs. For a long time, “a 12-inch port was all you could use in the hull,” Foster says. “Now, if you can prove in testing that a window can withstand the projected pressure, impact, twisting and vibration, it’s feasible.”

Glass pieces go into the furnace before they are curved into a final shape. 

Glass pieces go into the furnace before they are curved into a final shape. 

The Drawbacks

The pitfalls of more glass making its way onto boats include too little of other materials and too much light. “The bigger hole you cut for windows, the more compromised the hull becomes, the more you have to add structure inside,” Foster says. “You end up with bigger bulkheads you have to find a way to hide, and more weight.”

At the same time, flooding a boat with natural light can look and feel good, but it also introduces ultraviolet rays, which add heat and fade fabrics and furniture. Some glass can be tinted, but laminated tints can cause broken glass to remain in sheets, which is dangerous. And, construction standards dictate that any window in the line of sight of the helm must remain clear. Counteracting the heat that comes with more ultraviolet rays often means larger air-conditioning systems and the larger generators required to power them, adding even more weight.

Taken together, the added weight of the glass, the internal structure and the systems increase cost, hinder performance and make boats less efficient, but designers are using various techniques to neutralize those problems.

“Smart design can counteract these effects,” Droogsma says. “It’s better to design an overhang that can block the sun than add A/C systems.”

Strum points to spray-on coatings being developed to defray ultraviolet rays, although they’re expensive. “Getting heat out of the boat is still the biggest challenge,” he says.

Foster says Sunseeker is mitigating the challenges by prioritizing its signature look and performance, sticking with “relatively small glass installations on the hull while going for it on the superstructure.”

This superyacht concept from Vripack includes side walls of glass and an aft glass deck.

This superyacht concept from Vripack includes side walls of glass and an aft glass deck.

The Future

Despite the difficulties that using more glass brings, future boat designs are likely to include more of the material, including in staircases and as part of in-deck skylights as well as lookout stations below the waterline. The trend of adding glass is now being seen in boats of virtually all lengths.

“It’s starting to dive down into the 50s, 40s, 30s,” Strum says. “There’s a lot of interest among buyers, although it’s not yet totally cost effective at that level.”

The custom market will continue to drive innovation, according to Dr. Anna Buksak, head of technical support for YachtGlass in Germany. “The requirements and ideas for custom yachts are very often a motivating force for innovation and specific solutions in our products,” says Buksak. “Fulfilling the owner`s wishes often leads to discovering useful applications for general production which we later include in our range of solutions.”

YachtGlass has had technical successes like widebody windows that looked like standard windows but opened to create a “VIP” entrance to the yacht. The company has also installed glass railings around a deck without any steel parts or reinforcements.

On superyachts, Droogsma sees glass being used lower and lower in the hull.

“Underwater glass will become more and more common,” he says. “It’s still difficult, but clients want it.”

Foster recently toured a 164-foot megayacht with an underwater viewing room that had a glass panel about 12 feet wide and 6 inches thick.

“It had that wow factor,” he says, “and it will trickle down. People are going to want that aquarium effect.”

Now that will be something to see. 

This article originally appeared in the October 2019 issue.

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