17 How to interpret the sounder screens

With practice and experience it's possible to interpret the echoes on the sounder screens quite accurately. You can learn to recognize different fish, the type of bottom, and shadows.

The water depth, the scroll speed and the echo strength can affect the quality of the display. The range and gain settings can also affect the amount and quality of echoes returned.

17.1What are fish arches?

In good conditions, a fish swimming through the sonar cone will usually be shown on the Sounder screen as a fish arch.

A fish arch starts when the fish first enters the edge of the sonar cone, generating only a weak echo. This appears as the thin leading edge of the fish arch on your Sounder screen.

As the fish swims towards your vessel and the center of the sonar cone, the echoes are returned more strongly and more frequently. This means that the fish arch increases in thickness and is shown at progressively shallower depths. This produces the first half of the fish arch, which peaks as the fish passes through the center of the sonar cone.

As the fish moves away from your vessel towards the edge of the sonar cone, the reverse happens, producing the downturned side of the fish arch on your Sounder screen.

17.2Problems with fish arches?

There are several reasons why fish may not always appear as fish arches on your Sounder screen. For example:

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when you're at anchor, the fish appear as horizontal lines on the Sounder screen as they swim in and out the sonar cone. A slow boat speed is more likely to produce fish arches, especially in deep water

when you're in shallow water, the sonar cone is very narrow because it doesn't have time to spread out, so the fish don't stay within it long enough to generate a good fish arch on the display screen. Instead, the fish tend to appear as randomly stacked blocks of pixels

when the water is choppy, the wave motion can distort the fish arches the transducer may not installed in the best position

the range and range shift may need adjusting to show a smaller vertical extent of water. Also try using the split zoom screen to increase the resolution. It can be easier to see fish arches when the Sounder screen is concentrated on a smaller area of water, rather than displaying everything from the surface to the bottom.

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Northstar 8000i Operation Manual

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NorthStar Navigation 8000I How to interpret the sounder screens, What are fish arches?, Problems with fish arches?
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8000I specifications

The NorthStar Navigation 8000i is a sophisticated marine navigation solution designed to enhance the safety and efficiency of marine operations. Utilizing the latest technology and innovative features, the 8000i provides users with a comprehensive navigation tool that is both user-friendly and highly reliable.

At the heart of the NorthStar 8000i is its advanced GPS integration, which delivers precise positioning and navigation capabilities. The system supports multiple satellite systems, allowing for exceptional accuracy and reliability in determining a vessel's location, even in challenging conditions. The 8000i uses Differential GPS (DGPS) to further improve positional precision, making it suitable for commercial vessels and recreational boaters alike.

One of the standout features of the NorthStar 8000i is its large, high-resolution color display, which presents information in a clear and accessible manner. The screen offers customizable layouts, allowing users to prioritize the data they find most critical. The interface is designed with simplicity in mind, enabling users to access navigation tools, charts, and other features quickly and easily.

The NorthStar 8000i is equipped with advanced cartography options, including support for a variety of chart formats. Users can choose between vector and raster charts, ensuring that they can find the best option for their specific needs. The system also supports both local and regional data, providing an extensive coverage area for vessels operating in different waters.

In terms of connectivity, the 8000i features integrated networking capabilities, allowing it to interface seamlessly with other marine electronics such as radar systems, autopilots, and AIS transceivers. This interoperability enhances situational awareness and provides a comprehensive picture of the marine environment around the vessel.

The rugged design of the NorthStar 8000i ensures that it can withstand the challenging conditions often encountered at sea. Built to be weatherproof and durable, this navigation system is ready for any marine adventure.

To summarize, the NorthStar Navigation 8000i combines cutting-edge GPS technology with user-friendly designs and exceptional features, making it a top choice for navigators seeking reliable marine navigation solutions. With its accuracy, customizable interfaces, and robust construction, the 8000i is engineered to meet the diverse needs of modern sailors, whether for leisure or professional undertakings.
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