Sea And Be Seen
When the custom yacht DAR debuted at the Monaco Yacht Show in 2018, she generated a lot of buzz. It’s hard for a 295-footer with a dramatic black and white profile not to be a major conversation starter. Still, the most talked-about aspect was the extraordinary use of glass. Designed by Luiz de Basto and built by Oceanco, DAR is dominated by darkened glass spanning the main deck to the sundeck, attached directly to—not fitted within—the aluminum superstructure. Altogether, it’s nearly 4,300 square feet of glass. Equally remarkable, despite it blending into black-painted areas outside, the glass is completely transparent from inside.
All 188 panes, each six by 10 feet, were custom-made at the Tilse production and glass-bending factory in Germany. The facilities are in the farm-dotted countryside, several hours’ drive from the closest major port city of Hamburg. It’s a seemingly unlikely place for manufacturing massive windows (far too big to be to be called “ports”) meant to be fitted to equally massive superyachts lying in wait hundreds of miles away. Yet, for the past four decades, the family-run company has specialized in it. Owners of superyachts increasingly want windows whose dimensions and locations were just as unlikely only a few years ago.
Tilse dates back to 1974, when Hans-Joachim Tilse acquired his employer, a glass company manufacturing windows for a variety of industries. Responsible for traditional ship ports, he had grown the marine division to the point where it represented 75 percent of the business. Ten years after buying the company, Tilse added yacht glass as a specialty. Over time, since Germany and its neighbor, The Netherlands, are home to a number of superyacht shipyards, superyacht-specific glass became an additional business line. Yachting customers eventually eclipsed commercial customers to the point where Tilse now only focuses on the leisure market.
Hans-Joachim Tilse led the eponymous company until his death in 2018, when his daughter and son-in-law, Frauke and Henning von der Thüsen, began co-directing. Today, about 40 craftspeople handle measuring, manufacturing, and installation, with two-thirds of the business being custom yachts of 164 feet and larger at shipyards like Feadship and Oceanco in The Netherlands, and Lürssen and Abeking & Rasmussen in Germany. A small portion of Tilse’s new builds take place in American and Finnish shipyards, too, with the remaining one-third of Tilse’s business being refits.
Regardless of locale, each project has a common challenge: “We don’t step onboard the first day [of construction],” Henning von der Thüsen says. In fact, “The yacht is already one to one-and-a-half years in development at the yard” when the von der Thüsens enter the picture. The timing is when the shipyard wants all openings to be closed, Henning adds, but whenever possible, Tilse prefers collaborating with designers in the early design stages, especially to prevent rude awakenings. Mr. von der Thüsen recalls a past conversation that had him explaining to a designer that no machinery in the world could manufacture their request: a 13-foot by 13-foot window.
Yet thanks to Tilse’s unique ingenuity and capacity, much of what designers and owners want is actually possible. Whether it’s floor-to-ceiling windows without mullions, curved skylights, or glass for underwater viewing lounges—one such window measures 12 feet long by six feet wide—Tilse makes them, and further, manufactures the resins for mounting them. Additionally, Tilse uses a chemical toughening process rather than a thermal one. With chemical toughening, glass is submerged in a bath of a molten potassium salt solution. Global glass makers report this results in higher strength and less distortion. The process also allows for the creation of thinner panels. While thermal toughening is not inherently bad, the rapid heating and subsequent rapid cooling can cause distortion. If you’ve ever seen waves or ripples in yacht glass, they’re probably from the rollers that moved the pane through the thermal process.
Once panes are toughened, there’s still work to do. Tilse’s craftspeople suspend the pieces in front of special lighting for inspection. They meticulously examine every inch of the glass for flaws with a low-tech magnifying device called a loupe and mark them accordingly.
Frauke and Henning von der Thüsen also alert the owners’ representatives, designers, and/or shipyard that the glass is ready for their viewing and approval. The review is usually just a few minutes, they say, though one team a few years ago wasn’t satisfied with inspecting the glass the standard way. Apparently convinced they were missing some potential flaw, they spent hours examining the pane at the factory. Tilse’s craftspeople even transferred the hefty glass outside to mimic real-life conditions. The result? “They couldn’t find anything,” Frauke von der Thüsen says.
Achieving the acceptance standard is one thing. Transferring these massive panes to shipyards hundreds or thousands of miles away is entirely another. So is installing them, especially when the panes have to go up high and be maneuvered around scaffolding and related construction equipment. Tilse’s own team wraps, packs and transports the glass, then handles all aspects of fitting. The latter comes courtesy of The Monster, the apt nickname Tilse has for a piece of machinery the company made just for those tasks. It consists of a substantial, extendable arm—boldly painted red—with arguably the largest suction cups you’ll ever see mounted at its far end.
In another example of necessity being the mother of invention, Tilse was on the working group that set ISO standards for yacht glass several years ago. Working within such an ages-old industry and finding new avenues to stay ahead of the curve, so to speak, is paramount to survival, so R&D remains front and center, too.
Recently, Tilse and a partner developed a resin that changes from transparent to opaque once the outside temperature hits 95 degrees. It reduces heat transfer while still allowing diffused light to enter, suiting so-called winter gardens, the equivalent of a glass-enclosed sunroom, as an alternative to blinds. It’s pricey, though—even for a superyacht customer—so it hasn’t yet found the right match.
Curved or straight, small or significant, every order comes with its challenges. Like the owner of DAR, customers are never content with “just” a window. Luckily, neither is Tilse.