CoreMarine & Under - The Worlds Largest Underwater Restaurant

Oslo, Norway: Europe's first underwater restaurant. A challenging installation on Norway's southern coastline. A monolithic structure made from environmentally-sensitive materials, merging into its rocky surrounds, forming the foundation for a marine life research center. As hydrodynamic and installation engineers dedicated to furthering the blue economy, the opportunity to work with renowned architecture firm Snøhetta and their latest project, Under, is the chance of a lifetime.

This project epitomises the aim of CoreMarine to transfer technology and knowledge from the oil and gas sector into emerging ocean industries.
— Ben Fitzgerald, CoreMarine AS

CoreMarine has partnered with FFS and Einar Øgrey to form SubMar Group, which as a Joint Venture will execute environmental analysis, transport and installation for this unique project. The restaurant will be situated at Båly, a small town near Norway's southern-most point. Project owners Gaute and Stig Ubostad own and operate the Lindesnes Hav Hotel adjacent to the restaurant. Work is expected to be completed and the restaurant opened in early 2019.

The project poses numerous technical challenges all constrained by a very tight budget for the size of the project.

"In oil and gas projects we're used to seeing bigger budgets for T&I [transport and installation] projects like this," explains Ben Fitzgerald, Project Manager for Marine Operations. "We have to keep operations as efficient as possible while not risking the integrity of the structure".

Fitzgerald, who used to work in the oil and gas industry, also said that while many other ocean installation projects choose function over form, it is the form and design of this structure that takes precedence over any functional issues. He explains: "the restaurant doesn't even float horizontally, hence why we have to use a HLV [Heavy Lift Vessel] to maneuver it into position. If this was an O&G project, we would just change the design".

Positioning the restaurant with the Heavy Lift Vessel 

Positioning the restaurant with the Heavy Lift Vessel 

The restaurant will be constructed entirely on a barge and then towed into position. Installation operations will then follow with barge submersion, floating off the restaurant and placing the structure into position with the help of a Heavy Lift Vessel.

    Technical details of the restaurant include:

    • Installation Depth: 5.5m
    • Weight: 1640 tonnes
    • Wall thickness: 500mm reinforced concrete
    • Panoramic Window: 11m long, 42cm thick
    • Capacity: approx. 100 guests

    In addition to the installation work, SubMar has performed wave propagation and wave loading analysis for the structure. This analysis covers both structural considerations for the restaurant structure, while also providing an important tool for the marine research project that will co-exist with the restaurant.  

    Unstructured mesh around restaurant window used for CFD analysis. 

    Unstructured mesh around restaurant window used for CFD analysis. 

    Developed by leading Nibio marine biologist Trond Rafoss, the structure will facilitate research on fish behavior and the surrounding marine ecosystem. The analysis performed by SubMar will allow the flow profiles and current speeds at various depths to be studied and the seabed conditions optimsed to ensure marine life thrives in close proximity to the restaurant's statement viewing window. Discrete lighting will ensure guests are able to see out into the depths. Over time, mussels will take over the outer walls, forming an artificial reef which filters the water and attracts more marine life.

    This restaurant may only be the start. There are plans for further developments of underwater spaces and joint marine research projects internationally.

    "We see a future where underwater spaces that co-exist harmoniously with the surrounding ocean environment are common place and accessible for all to enjoy," says Fitzgerald.

    Under has already captured the attention of global media outlets including CNN, Time and Business Insider. Local Norwegian media including NRK, Aftenposten and DagensNæringsliv have also covered the project.