Advances in Electronics and Trawl Technology
Advances in electronics and trawl technology are taking some of the guesswork out of finding fish, making the harvesting of those fish more efficient and environmentally sound, and improving the efficiency of hauling them aboard.
One of these advancements is the complete line of electric winches recently delivered by Rapp Marine for the O'Hara Corporation's DNV-classed, 194-foot stern trawler F/T Araho, ensuring the vessel is fully equipped for bottom and pelagic trawling. This is the first US trawler to be produced since the early 90s.
In total, the deck equipment includes two electric trawl winches, two electric gilson winches, two electric double net drums, one electric single net drum, three electric cod end/outhaul winches, one electric net sounding winch, two hydraulic anchor winches and one hydraulic capstan.
In addition to the deck machinery, Rapp also supplied a complete control system using the Pentagon CBus F control and monitoring system, which controls auto payout, haul back and towing operation of the trawl winches and the system. The system also monitors real-time trawl length, speed and tension, and logs all of the data produced.
There are 17 and 19-inch touch screens in the wheelhouse control station and joysticks for all winches. The trawl winches can be controlled from the captain's chair and there is an aft control station in the wheelhouse operating all winches. Wireless controls supplied, which control all winches, are the primary controls used during fishing operation, and there is a permanently mounted control station on the port side of the working deck.
"The Pentagon CBus system is like a networking set up," says Johann Sigurjonsson, President, Rapp Marine US. "It simplifies the installation for the shipyard and is more economical for the ship owner."
The two TWS-22030E/S6 model trawl winches will perform the bulk of the work in the fishing operation, each with the pulling capacity of 45 tons and the capacity to hold 2,800 meters of 32 mm cable.
The trawl winches are powered by Rapp Marine's unique gearbox design, with multiple fluid-cooled electric motors installed onto the gearbox. The winches have electric level winders and LeBus shells to ensure correct spooling of the wire. The trawl winches have reinforced drums to handle Spectra (Dyneema) rope
"Our unique gearbox design provides built-in redundancy," says Sigurjonsson. "If you have a problem with one motor, you can keep on fishing with the others you have left."
The vessel is fully equipped with a state of the art system, which includes Patented Liquid cooled Electric Motors. The trawl winch system is designed for regeneration of power from the trawl winches using an ABB DC grid solution manufactured by ABB Marine. The ABB primary and redundant incomer rectifier systems are designed to operate with an electrical service of three phase, three wire ungrounded circuits supplied with a nominal in feed voltage of 480 VAC at 50-60 Hz.
"Years ago, the industry was using electric winches. Then hydraulic winches were used because they had better control," adds Sigurjonsson. "Now with the advent of the frequency controller, using an electric system is back on the board again."
NET Systems, located on Bainbridge Island, Washington, with offices in Kodiak and Dutch Harbor, Alaska, offers a wide range of trawl netting for several fisheries including bottom and midwater trawls as well as cod ends and trawl doors. In business since the 1978, the company has consistently worked to improve their products for cost-effective fishing.
Right now, NET Systems is developing improvements to its four-stranded, continuous filament strands through the Ultra Cross (UC) knotless netting called Ultra Cross Polyethylene (UC PE), to make it last longer and be more abrasion-resistant. "The UC netting has improved fishing because of its strength for a single layer cod end and the improved water flow," says John Adams, Sales Manager.
Using the Ultra Cross four-strand provides the UC netting nearly 100 percent of its original twine strength throughout its life due to the four-stranded braiding process. It also helps fishermen with the bycatch challenge. "It lends itself to making cod ends out of square mesh," explains Adams. "The opening provides access for unwanted species to get out in a hole size that accommodates them."
The quality of fish is improved due to the knotless design as synthetic fibers lose from 30 to 60 percent of their strength when knotted. "Typically the fish get squished against the knots inside the bag and the quality of the fish is compromised. Fishermen lose money during processing," says Adams.
The UC netting is also made in one single layer as opposed to earlier industry trends of using double or triple layers, which were more expensive and harder to tow. In one shrimp customer example using the UC Silver netting, the operator's towing expenses were reduced by nearly a 20 percent reduction of fuel consumption, his catch rate went up and there have been no tear ups with the product.
"We've seen 10 to 15 tear ups in our shop in the last two months and his nets have not appeared here," says Adams. "It's amazing to see this Dyneema netting in the UC Silver format really paying off. Because every time a guy brings a net in here, it's at least $2,000 to $2,500 to repair, depending on how much damage a guy does."
NET Systems' trawl door series 2000 was introduced about four years ago with two options; "V" and straight doors. The doors keep the trawl open throughout the turns and maintain the opening as the cod end fills. Doors are reinforced at all critical stress areas and have alloy steel construction which allows for long durability with minimal maintenance.
Improvements have also been made and the newer doors have a better cohesion of lift and stretch that provide enhanced spread, improved towing resistance and better fuel consumption.
Adams says some customers have had doors that have lasted 20 years. "Those have worked very well for different reasons. The V doors are for boats that have dual fishing," he says. "But now we need to find a better alternative. The door is about 2.2 aspect ratio and we want to improve on that as well as maintain the doors' stability."
Earlier this year, Furuno announced their new multi-station integrated navigation network, dubbed the NavNet TZtouch2. The company says the multi-touch, multi-function device (MFD) has been refined to be even more intuitive than the original NavNet TZtouch.
Furuno is now including a proprietary built-in dual-frequency Fish Finder (50/200kHz with 600W/1kW power output) in the MFD, and the new digital signal processing proprietary system called RezBoost has the capability to produce fish targets and images that are up to eight times sharper than a conventional Fish Finder, without the need to change out a narrowband transducer or purchase an expensive broadband transducer.
"With RezBoost, you can now achieve target separation and resolution that was previously limited to Furuno commercial-grade Fish Finders," says Jeff Kauzlaric, Furuno's advertising and communications manager. "It also includes Furuno's unique Bottom Discrimination and AccuFish modes. This built-in Fish Finder saves at least $900 over earlier NavNet systems."
The TZtouch2 system features an all-new, refined user interface that makes it even easier to use. Bold, bright colors denote specific icons for selected displays that include radar, chart plotter, instruments and more. Operators can move between displays by tapping on the Home icon or by utilizing the new "Edge Swipe" motion. Swiping down from the top or swiping from the left or right allows faster access to data displays rather than having to navigate through menus.
A number of Furuno components can be added to the network as needed. For instance, customers can choose from a 12.1-inch WXGA or 15.6-inch FWXGA multi touch display that utilize raster and vector charts in MapMedia format based on Jeppesen, Navionics and NOAA data.
The TZtouch2 system also works on tablets and smartphones via WiFi. There are several free apps that can be used on Apple and Android devices. Furuno has plans to expand more wireless capabilities that will include the capability to access CommunityCharts and a back-up Cloud Data Service.
Simrad's Michael Hillers, General Manager of the Lynnwood, Washington company, reports that trawl monitoring equipment is in demand as fishermen want to save as much fuel as possible when fishing and also want to deal effectively with bycatch.
Knowing what's happening with the door spread, in particular, is important. "Traditionally the doors just clunk down on the bottom, where they're dragged in order to herd fish," he says. "There are environmental reasons why having the door off the bottom is a better idea. A door dragging through the water also uses significantly less fuel than a door dragging on the bottom."
Sensors can tell fishermen the spread, the roll, the depth, the pitch and height of the doors. "Generally in a pelagic fishery where you've got fish in the water column, the depth of the doors is more important than the height off the bottom," explains Hillers. "You can see on your echosounder where the fish are."
"The fish are down at 70 fathoms and the bottom might be at 500 and you want your doors to get down to the depth of the fish so they have the ability to herd the fish," he continues. "At that point, you might not be able to read how far the door is from the bottom but you can get the pressure depth so you can tell how far it is from the surface."
However, for some fisheries, with long sweep lines from the doors to the trawl, there is contact desired with the bottom. A bottom contact sensor can be put anywhere on the net or sweeps and adjusted as necessary to show contact.
What sensors do is gather all the data and allow fishermen to view it either in numeric or graphic form. This helps give a real-time, easy to understand view of the state of the nets that takes a mere glance to evaluate while fishermen are evaluating other equipment and keeping an eye on people on deck.
The Simrad PX TrawlEye uses acoustic communication to transfer the echogram data from the trawl to the bridge display. It has adjustable parameters to "tune" it depending on operational requirements for different type of fisheries. This includes the echo range, which can be extended to 100 meters, ping rate, gain and resolution.
The hydrophone communication frequency range is 39 to 49 kHz. The maximum range depending on sea conditions is 1,200 meters. The TrawlEye echogram is updated every one to seven seconds. Roll, pitch, temperature and depth data is updated every 20 seconds.
For ease of trawl sensor installation, a deployment housing pack can be mounted permanently on the trawl and rolled up on the net reel. This housing pack also allows easy and quick removal for charging and reprogramming, if necessary. Reinstallation of the PX TrawlEye or PX MultiSensor in the exact (proven) location takes just a few seconds.
The Simrad PX MultiSensor offers customizable programming and helps reduce the need for multiple sensors or costly upgrades. It can be used to measure Pitch, Roll, Spread, Height, Depth, Temperature or Geometry and is equipped with the latest Li-Ion battery technology – the battery package and new charger offer longer operation time.
In 2007, in response to by catch issues, the company introduced the PI series of sensors to measure distances between points of a deployed trawl. Among other parameters, this allowed trawl manufacturers to measure excluder flaps; to show the flaps opening and how far they open. In conjunction with depth, the sensors and a recording camera placed strategically on the net, an idea of how the net was "flying" could be determined.
Now with advances in technology, real-time video feeds are a reality. The Simrad FX80 catch monitoring system does just that in order to monitor trawl and fish behavior. "What this allows you to do is to do real-time species identification," says Hillers.
Two different types of Simrad sonar systems also provide more insight into the nets. The FS70 330kHz sonar with 200kHz echo sounder provides a real-time picture of the trawl opening and position relative to the bottom. The operator can control the descent of the trawl during the set by monitoring both the depth and the position of the foot rope in relation to the bottom.
In addition, the sounder display provides an accurate depth of the bottom and the foot rope and the operator can monitor up to twelve catch indicators, indicating the amount of fish being caught by the trawl and the time when the sensors were activated. With a scanning sonar the complete net image takes about 90 to 120 seconds to be completed, the new FM90 multi-beam trawl sonar refreshes the screen every three quarters of a second, depending on range.
"With the FM90 multi-beam sonar, you get the entire net image at the same time," Hillers adds, "so one ping gives you the whole image."