Metal Rebuilding Window Profiles on a $58 Million Catamaran Yacht

In our post “Long-Term Marine Maintenance Made Simple”we discovered some of the most common Marine Industry problems that can occur due to the harsh natures of offshore conditions. For the most part, issues are caused by corrosion or erosion after years of operation. On rare occasions, however, we can also find problems occurring during the manufacturing stages, requiring corrections such as metal rebuilding.


This was the case when the structure of a luxury yacht (designed by a top sports car manufacturer) had already been built, with a sudden change in the type of glass chosen for the windows. The window profiles were not compatible with the glass thickness. Lower thickness of glass required greater thickness of the metal window profile. A material would need to be able to be built to a thickness of 1 – 1.5 cm (0.39 – 0.59 in) on to vertical frames.  

This type of failure would clearly not be acceptable to such a prestigious design. It was therefore highly important that the problem could be solved with precision and taking as little time as possible in order to avoid any delay in the delivery. 

Belzona Metal Rebuilding Window Profiles

“Everything possible had to be done to make a success of this crucial phase. Bearing in mind a very important point – our work could not hamper delicate work that was ongoing near to us simultaneously.” – Miguel Angel Hernández Casas, Regional Sales and Service Engineer, Rodator

The metal rebuilding needed to take place inside the 135ft/41.1m catamaran design. The $58 million craft features 472 square meters of interior space, accommodating 10 passengers and 10 crew members. There were 2 major affected zones in need of a solution. One of which was 148 linear metres long with a width of 5cm. The other being 68 metres long with a width of 10cm.


A solution was needed that would be capable of building up vertical surfaces to the required thickness without sagging.

Traditional welding repair methods were considered but had a potential of damaging wood furnishings and interiors near the windows, as well as being very expensive. Other work on the yacht was also taking place at the same time, meaning lack of space had to be considered. Therefore the nature of welding would not have been suitable. 

The customer turned to cold-applied metal rebuilding options. Materials from several manufacturers were considered and the decision was made based on slump resistance, as some vertical surfaces needed to be built up to 2.5cm.

Belzona 1121 (Super XL-Metal), a multi-purpose durable repair composite, was selected for the metal rebuilding. This would offer the use of moulds being a 100% solids epoxy material.  

Belzona Metal Rebuilding Window Profiles

Due to the large scale of the rebuilding, (around 300kg of Belzona 1121), an extended working life of the material was greatly beneficial. A working life of 35 minutes at 25˚C/77˚F ensured that the material could be worked with the moulds to the precise measurements without a stretch for time.  


The surfaces of the window profiles were initially prepared using a hand tool. As mentioned before, precisely measured formers needed to be created for the alignment of the windows. Wooden formers were cut out, with Belzona 9411 (Release Agent) being applied for later removal once the material had cured.

Belzona 1121 was worked into the surface of the former for a smooth finish. The material was then built up to achieve the correct thickness.

The former with the material was then applied directly to the surface of the window profiles and pressed with clamps to ensure the best possible finish.

Once cured, the formers were then removed and lightly abraded for an optimum finish.


The exact dimensions and geometry of the window profiles needed were able to be achieved, which was the fundamental part of the application, allowing the window glass to be fitted. The application was also able to be completed within the given deadline.

This unique example illustrates a very common problem in a wide range of industries. Belzona’s metal rebuilding solutions are easy to apply, require no hot work and dramatically reduce downtime. Rebuilding components using formers facilitates precise restoration, for example, for a shaft repair.

Belzona Metal Rebuilding Window Profiles
Part of the finished application


Watch the video below for another example of forming techniques used during a repair:

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