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How to Replace the Windows on Your Boat

The View Ahead

Custom windows can take the finish of your boat to the next level.

It’s hard to overstate the importance of windows on a boat. They keep out the wind, spray, and rain, and today’s high-tech glass can even reduce harmful UV rays, so that when you think you’re out of the sun, you really are. But saloon windows also offer those unbeatable views and often fresh air as well, two reasons why we take to the sea in the first place.

Arawak’s made-to-order Marex windows have anodized aluminum frames.

When the MyBoatWorks team first dove into the Arawak makeover, they created a list of projects and prioritized them. If you haven’t been following along, Arawak is the 1996 Grand Banks 42 Motor Yacht that has been the subject of a repower and extensive refit as part of the MyBoatWorks project ( 

A few of the projects fell into the must-do-to-be-safe-and-operable category (a two-engine Yanmar repower, shaft alignment, new Northern Lights genset, Simrad electronics), and a few slid into the secondary comfort category (Technicold air conditioning, replacing hatches), and still a few more were cosmetic. As terrific as new windows are, they’re not terribly necessary if the old ones are still firmly in place, don’t leak, and still open and close as needed.

A bead of caulk keeps out the weather.

That’s how they were on Arawak when we did our cruise to test electronics equipment and gear (see “Get Wired” in the May issue). They’re big windows, and they worked just fine for our needs, keeping the mosquitos and no-see-ums at bay in overnight anchorages. Underway, we opened the middle windshield pane and propped it on its sliding, hinged strut for ventilation. The breeze filled the saloon, taking the edge off the humidity as we crossed the Florida peninsula on the Okeechobee Waterway.

Long-term, however, replacing the windows was a great idea, since the originals were a pretty old-fashioned design. “They’re pretty good-size windows,” says Bob Walker, technical support representative at Vetus ( “We did the three large fixed windows across the front on the bridge and then one  large fixed and one smaller sliding window across the back of the main saloon. The way they originally did them at Grand Banks, they were fairly basic. They trim the rough openings out with wood inside and put in a piece of glass, then add more trim on the outside to hold the glass in place.”

Vetus, a Dutch company that supplies aluminum-framed windows, as well as other components, to many boatbuilders, provided custom-built windows for Arawak. If you’re interested in replacing the windows on your boat, the custom Marex windows from Vetus may provide just the look you’re after. They’re available in three ranges: The first is the screw-on range, which offers windows in an anodized aluminum frame with radiused or mitred corners. This design is considered suitable for boats with wooden superstructures. They’re available in fixed, sliding, and half-drop configurations. “The window and the frame are caulked and then slide into the rough opening,” Walker says. “Then they’re installed with fasteners—they can either be through-bolted or screwed in.” Fastener heads are then covered with a black or gray rubber strip.

Jay Stockmann of Vetus peels protective film.

The second is the comfort range, which uses a frame backed by a counter flange, which is then screwed in place from the inside. These windows are available with single-layer glass in fixed, sliding, half-drop, and combination versions. Double-glass versions are available in fixed, half-drop, and combi versions. “Those employ a clamping-type mechanism, so you basically insert the window into the rough opening, and then inside you have a frame that comes in,” Walker says. “The outside frame of the window and the interior trim piece clamp together, and there’s a rubber strip that covers the fasteners, so you have a nice clean finished look from both inside and out.”

The third level is the exclusive range, which uses a synthetic insulation layer between the frame and counter flange to prevent conduction of heat or cold and the attendant condensation. These windows are the best choice for boats that cruise in areas with temperature extremes.

There are some factors for the modern boater in considering custom windows. For one, Vetus prefers to have precise measurements to ensure an exact fit for the frame. “The typical boat owner is probably not going to be able to show up with accurate CAD drawings,” Walker says. “And to measure a corner radius, the average guy who’s sitting there with a pencil and paper is probably not going to give us something that we can work off. If we make them with their drawings and they get them and they don’t fit, it’s understandable that no one is happy.” This is one reason why the custom window program is a hit for builders to install in brand-new boats: The frames can be built from the actual design drawings. “We need very, very accurate drawings to do these,” Walker says. “Obviously when they’re building them into a new boat, we get the CAD drawings to work from.”

For the do-it-yourselfer to get the best fit, Vetus recommends removing the original windows and cleaning up the hole in the structure before measuring. If the boat’s builder is still in business, it may be worth a call to see if you can get the original line drawings from the company. And then careful measurement and a check of maintenance records on your boat will reveal if there have been any aftermarket shenanigans around the windows in the interceding period. “There are limits to how tight a bend we can make on that radius without deforming the aluminum,” says Walker. “And then there are other decisions: Typically most builders opt for anodized aluminum frames, but on Arawak, we did white powdercoat so they’d match the rest of the boat better. It adds to the cost of the windows but not significantly.”

That vent admits cooling sea breezes.

Knowing the glass spec is key to the process. “The customer needs to know what thickness and what tint he needs and how thick the structure around the hole is where the windows are going in,” Walker says. As with any custom job, both customer and manufacturer need to think about the details to know what it takes to get it right.

Two big factors in the mix are time and cost. After all, we’re talking custom windows here. “These things are custom-made—literally,” Walker says. “There’s a lot of handwork, and we have to order the glass. It’s definitely something easier for boatbuilders who need a production run rather than just one of each size. The screw-in range works for a lot of applications but the fancier you get, the more engineering time is involved, and the longer the production time. Depending on how involved it is, typically you could expect eight to ten weeks lead time for production plus time for shipping.” Window production is not based in the U.S., so windows are shipped by boat or air freight from Holland. Air freight is much quicker, but it can be expensive, especially considering the weight.

As for cost, the windows are custom, so every project is different. “It’s going to depend on the features that are on the window,” Walker says, “whether it’s sliding, hinged, or fixed, and what range it is. One small fixed window could run as little as $300 to $350 while a full boat could be $7,000 to $8,000 easy and up from there.” Best to do the measuring and planning early, and get the job done right.

This article originally appeared in the September 2016 issue of Power & Motoryacht magazine.