Nowadays maritime traortation has been developed into many fields such as passenger traort, military purposes and etc. Vessels for berthing at ports need a Safe place without the dangers of sea waves. Using the breakwaters at port is one of the ways to protect the port against the wave attack. Generally breakwaters justify; LINE-HEIGHT: normal; TEXT-INDENT: 14.2pt; MARGIN: 0in 0in 0pt; mso-layout-grid-align: none" The purpose of this experimental study is to investigate the effects of the structure shape on breakwater efficiency, mooring forces and structure movement. In this experimental study two shapes of floating structure has been investigated. The studied floating breakwaters configurations are a rectangular, and a trapezoid with the slope of 60 degree. In order to moor the structure, four galvanized steel cables by diameter of 2 mm were employed. Mooring cables were connected to the bottom of the flume at a ratio of 3:1. The cables used in this study had been pretension. The experiments were conducted in the wave flume at the Subsea R D Center of Isfahan University of Technology. The wave flume of Subsea R D Center has a length, width, and height of 110, 3, and 2.5 meters, respectively. The wedge type of wave generator was used to generate regular wave with the period of 0.9 s to 1.4 s. At the end of the flume, a wave absorber was installed to dissipate the wave energy and prevent wave reflection from the end of the flume. The water surface level was measured using four wave gauges installed around the breakwater. Three wave gauges were installed at the sea side of the structure which were used for measuring time series and separating incident and reflective waves, while another was used at the beach side for gauging the transmitted waves. Accuracy of these wave gauges was 1mm and sample frequency was up to 50 Hz. Also one S-type load cell capable of measuring tensile strength, were used to record the mooring line. Experimental results of this study have shown that cross section of floating breakwaters is a fundamental design parameter of a floating breakwaters in order to achieve greater wave dissipation. The trapezoid floating breakwater results showed an overall improvement in efficiency of the structure in comparison with a typical rectangular one. The trapezoid floating breakwater shown reduced wave transmission and increased energy dissipation. Also results shown that mooring forces decrease with increasing draft unlike in the rectangular one increasing draft cause to increase mooring force. Key Word Pontoon, Floating Structure, Wave, Mooring Force, Heave, Sway, Load cell, Deep Water .
