Tuna Fish Trawler “Proud Mary”
In the year 1955, a structural change was made in tuna fishing in the United States. While in Europe, the first stern trawlers led to a new development in the field of trawling, the transition in the USA went from pole-and-line fishing to purse seine fishing. This new American method spread extremely quickly. The fundamental feature of this method is the use of a so-called power block. The purse seine nets, which have a length of 800 to 1,000 metres, are attached to floats in the water at the top, while the bottom edge is drawn by chains at a depth of up to 100 metres. This purse seine net is let down beneath the stern of the trawler and, with the help of a special dinghy, is spread in a large circle round the detected shoal of fish.
After the circle has been closed and the other end of the line has been passed from the dinghy to the trawler, the bottom part of the net is drawn together by a hydraulic winch, creating a huge pouch (like a purse, hence the name), from which the fish cannot escape. The trawler is now lying at the outer side of the ring and, by means of the hydraulic winch, now begins to heave the net on board. For this purpose, the power block is fixed to the end of the derrick, by which the heavy chains are also brought on board, using other hydraulic winches. Finally, with another smaller derrick, the fish are brought on board using large landing nets.
This model boat is based on a trawler with a length of 19.8 m, a width of 5.3 m and a draught of 2.4 m.