25 Years of Trawl Winch Technology
August 1, 2018
The first automatic trawl winch controls were launched by the Rafboði Company, later changed to Naust, in Iceland, in the year 1981. From that point on, companies have been working to innovate trawl technology, promoting the advantage of electric winches versus hydraulic systems. Among these, Naust developed their Automatic Trawl Winch (ATW) system as an efficient and reliable winch control system that could withstand the harsh conditions on the Icelandic fishing grounds and meet the high demanding expectations from the Icelandic trawler captains.
Electric winches are economical and environmentally friendly. Electric winches save fuel when compared to similar systems that use hydraulic or other energy sources, require less maintenance, and are easy to install.
Originally, efforts were focused almost exclusively on fishing trawlers in Iceland, but later efforts produced winch systems and power management systems (AutoGen), for research vessels, for load sharing and to synchronize the running of the generators on board vessels. The aim of utilizing the generators in the most efficient way possible to get the most out of the system is important in newbuilds, as well as in older vessels, and many have invested in the power management systems to improve their existing systems.
As the trawler fishing fleet in Iceland declined around the year 2000, demand for winch systems also declined, and manufacturers moved into foreign markets. This expansion introduced these modern systems to shipowners abroad who had shown an interest in using electrical winches but had some trouble in finding the right arrangement for auto trawling systems fitted for electric winches.
In most trawl winch controls, including fishing winches in bottom and pelagic trawlers, as well as other types of winches where constant tension and speed is required, the load is constantly measured by electrical current in the winch motor. From there, the load on each wire and the load sharing is calculated to adjust the tension equally on both wires. By maintaining the equal load on both wires, when wire length is adjusted, the fishing gear (the trawl) is kept in its maximum fishing condition (maximum geometry of the trawl). This will maximize the fishing efficiency of the trawl and at same time reduce fuel cost in the main engines and the amount of maintenance required on the trawls.
Recent innovations make it possible to take the signals from various trawl sensors to control the trawling winches and keep the trawls in a preset position and distance to the bottom. These new systems can be connected to sensors from Marport, Simrad and Scanmar.
In cooperation with the Iceland-based data software company TrackWell, it is possible to collect various historical data about the fishing at every point that the trawl is in the water. For example, sensors report the wind force, fishing depth, position of the trawl doors from the bottom, water temperature at the trawl and at the vessel's keel, trawling time, course, fuel consumption and catch rate per hour and much more information. With this information stored and accessible by the captain and the owner's representative, it is easier to compare years, fishing seasons, vessels and fishing in certain areas. The data may also be used to compare fishing activities and various factors, between two or more vessels within the same group.
In the latest newbuilds for bottom fishing trawlers, there is high demand for improved dynamics in the trawling winches. Innovations now exist to keep the trawl in steadier contact with the bottom in bad weather, where the vessel may move rapidly in heavy swell. This results in improved fishing per fishing hour, less fuel used per pound of fish caught and less maintenance of the fishing gear. It was long believed that electrically-operated trawls had to use big permanent magnet motors for running the winches. After much study and design work, Naust has developed a new trawling winch design that delivers high dynamic performance while increasing redundancy by 50 percent compared to older versions. The new design uses standard AC induction motors from any manufacturer.
As the technology advances, more newbuilds and refits can expect to see savings by migrating from conventional systems. We can expect the future of fishing to be electric.
Helgi Kristjánsson worked on trawlers in Iceland for more than 20 years, 14 of these as captain. He joined Naust Marine in 2003 as part owner and sales and marketing manager.