Port of Brownsville Floating Breakwater

The present paper describes the technical aspects of a new floating breakwater concept that was installed at the Port of Brownsville Marina located in Port Orchard Bay, Washington State, in 1999. The breakwater incorporates submerged porous treated timber "wave fences" installed on either side of the concrete pontoons to reduce wave transmission. Eight concrete pontoon units are connected to each other by a patented rubber cushion shear tube and bolt assembly on each side of the pontoon, and are held in place with steel anchor piles. A numerical model based on an eigenfunction expansion method was developed to study floating breakwaters equipped with pairs of wave fences of different porosity. A physical model test was conducted to study the performance of the breakwater under the action of oblique waves. A structural model was used to compute the design force envelopes for the concrete floats, using transient wave loads from the model studies as input. The unique solution developed in this project provides a cost-effective option for coastal and marina protections using floating breakwaters.