EU requirements are to install underwater monitoring windows for fish passes.
They serve the purpose of monitoring fish stocking status. These are large windows with thickness between 50 and 70 mm. With the aid of our chemical compounds we are able to install acrylic directly to the reinforced concrete. It requires a thorough grinding and strict plane preservation. Concrete must not have empty spaces and loose inserts.
This set of underwater windows was challenging in installation as we needed to use a barge to transport it. Then we had to collect panel from it using crane.