Fabrication of acrylic viewports

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At U-Boat Worx it’s our mission to offer explorers the best possible view from all our subs, including the deep diving submarines.

Our submersibles feature the largest and thickest acrylic windows ever made, and our engineers carefully design components so they don’t obstruct the view. Our acrylic viewports are created by specialist companies that have the ultimate levels of craftsmanship, only using highest- grade materials to ensure the clearest acrylic.

Each Cruise Sub for example has two acrylic hyper-hemispheres and one pilot window. The acrylic of the deep diving windows is incredibly thick – more than 20 cm (7.8 inches). Our suppliers have been making the lion’s share of acrylic viewport windows in the world, including those used in U-Boat Worx deep diving submarines.Thanks to ingenious engineering methods, we can deliver hyper-hemispherical acrylic viewports that are cast in one continuous piece, with no bonding required.

After the design of an acrylic viewport has been approved, the production starts. A mixture of powder and a liquid formula are combined in exact ratios in a specially constructed mould. After the mould has been filled, it is subjected to high pressure in an autoclave, and the temperature is slowly raised in order to initiate the polymerisation process.

After cooling the raw casting of the acrylic dome or hyper-hemispheres, it is removed from the mould. The raw casting is machined into its final shape over several stages. After each phase, the raw casting is re-heated (annealed) to release any stress that may have developed in the material.


When a perfect sphere with the specified thickness has been achieved and the viewport has finally cooled down, the polishing process starts.

Upon completion of a window, it undergoes a visual inspection and is measured, before entering our testing program, which include a wide range of trials including the major hydrostatic pressure tests of the complete pressure hull.

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