Curved Aquarium Window: Ozeaneum Stralsund

Client: Ozeaneum Stralsund (German Oceanographic Museum)
Location: Stralsund, Germany (UNESCO World Heritage Site)
Application: Spherically Curved Viewport & Aquarium Glazing
Glazing Volume: $5 Million USD (Contract Value)

The Ozeaneum in Stralsund is one of Europe's most ambitious public aquarium projects. Its engineering centerpiece is the Krypta, a massive schooling fish tank held back by a 13-meter wide (43 ft) spherically curved acrylic viewport. Unlike standard flat glazing, this installation required complex thermoforming to create a seamless, immersive view into the 8.5-meter deep tank.

Hydrosight acted as the sales representative for this project, securing the contract for over $5 Million USD in structural acrylic. While the physical installation was executed by a partner, Hydrosight successfully coordinated early stage of the supply of the 31 custom underwater windows that define the visitor experience.

The Engineering Challenge: The Krypta

Glass is rigid and brittle, making it nearly impossible to use for large, complex curves like this. This project demonstrates the unique advantages of Thermoformed Acrylic (PMMA):

1. Spherically Curved: The monolithic acrylic block was heated and formed to the exact radius of the concrete opening. This eliminates the need for vertical mullions (posts), providing an uninterrupted panoramic view.
2. Safety at Depth: At 8.5m deep, the hydrostatic pressure is immense. Acrylic is ductile and shatter-proof, eliminating the risk of spontaneous breakage—a critical safety factor for public aquariums.
3. Optical Clarity: Despite the extreme thickness required for this load, the acrylic maintains high light transmission (approx. 92%) without the green tint found in thick glass.

Why Curved Acrylic (PMMA)?

Glass is rigid and brittle, making it nearly impossible to use for large, complex curves like the Krypta. This project demonstrates the unique advantages of Thermoformed Acrylic:

1. Spherically Curved: The monolithic acrylic block was heated and formed to the exact radius of the concrete opening. Unlike laminated glass, which would require segmented panels, acrylic provides a seamless, uninterrupted view.
2. Safety at Depth: At 8.5m deep, the hydrostatic pressure is significant. Acrylic is ductile and shatter-proof, eliminating the risk of spontaneous breakage—a critical safety factor for public aquariums.
3. Optical Clarity: Despite the extreme thickness required for this load, the acrylic maintains high light transmission (approx. 92%) without the green tint found in thick glass.