Floating Net Pens

Floating Net Pens

Kropf Aquaculture has designed and manufactured floating structures for the aquaculture industry for almost 20 years.

Our experience and service have helped us to establish a reputation as the leading supplier for cage operations in northern freshwater applications that are subject to severe conditions and icing.

Our steel pontoon floating net pens have been designed to withstand the rigors of everyday use in an unforgiving environment, providing superior stability, performance, and floatation. Throughout our history, the designs and features of our systems have been refined based on the knowledge and experienced gained from both our aquaculture systems, and also our many commercial marina projects.

These rugged steel cages have been tested and proven in high energy sites on the Great Lakes, and have proven to provide a safe and secure cage structure and working platform for fish farming operations. We are equipped to design, manufacture, and install your system, and also provide excellent after-sales service to help keep your operations running smoothly and maximize your revenue potential.



Each net pen is constructed from spiral welded steel pipe, which serves as the floatation and main structural member. This gives the pen excellent stability, making it a safe and effective work platform. Steel framing to mount the decking is welded to the pipe.

Connections are made through a combination of bolt-frames with structural bolts and heavy-duty torsion rubber hinges. Each connection is braced with heavy angle-iron and gusset plates. Crossers and braces are saddle-plated to the main float pipe to distribute the loading and prevent oil-canning and fatigue.

All steel surfaces are sandblasted to white metal after construction. The pen section is then coated indoors in a climate controlled paint booth with Devoe Bar-Rust 233H. This advanced epoxy coating is approved for saltwater immersion, and provides excellent service life.


A variety of decking options are available. The most popular option is galvanized steel bar grating, as this yields the most durable and slip-resistant work surface. Other options include pressure-treated wood, cedar, and fiberglass decking panels.


A submersible option is available on all new floating net pens. Through a system of valves, bulkheads, and piping the floatation tube can be flooded, allowing the pen to be sunk below the surface, beyond the reach of ice movement and winter storms.

In the spring, compressed air is used to evacuate the tubes and raise the system, allowing it to be easily put back into service for the season.