How to use a Fish Finder

Technology is always evolving and this also applies to fishing. It seems that every year there are new types of fish finders, sonars, GPS’s and other gadgets that can potentially help you find fish. With so many types of products out there, its often hard to work out what you actually need and how to get the most out of it. We’ve spent countless hours tinkering with our electronics to try spot more fish and find new ground. So this guide should hopefully help you fine tune your setup and increase your success out there.

There are many brands out there all with their own buzz words and marketing. This can be a little daunting, but the good news is that most of the brand name gear out there is more than capable of working well. If you stick to the majors like Garmin, Lowrance, Furuno, Simrad,Humminbird and Raymarine you are pretty safe. The key is to work out which features you really need.

Working out what you need will help you get something without being unnecessarily upsold to the top of the line gear. Things to consider before you start shopping are:

– What depth are you planning on fishing in?
– Are you fishing in fresh or salt water
– What kind of boat have you got (Aluminium, Fibreglass, inboard/outboard)?
– What type of fishing do you plan to do? (Trolling, bottom bashing, jigging…)
– Do you want to have 1 or two screens?

If you can answer the above, you are ready to start looking at the technology out there. A good shop should be able to work out what will suit you best in terms of transducer type, mounting, power etc… But here is a quick summary of what everything means:

– Transducer type:
There are a few main transducer types, the most commonly used in recreational fishing are the transom mount and the through hull type. The transom mount works with outboard engines only, but suits almost all hull materials and is a quick and easy part to install. The through hull types are great for both inboards and outboards, but you need to make sure you chose the right material based on your boat. Through hull transducers work exceptionally well at higher speeds as well. The installation is a little more involved and you need to drill a hole into your hull. So many people who are keen to DIY stay away from Through Hulls.

– Transducer Frequency:
Up until a couple of years ago, you would only see dual frequency transducers (50-200kHz) which made things pretty straight forward. Recently, many brands have released cost effective CHIRP sounders which can support a new range of transducers. These transducers generally have 3 ranges of frequency, Low (L), Medium (M) and High (H). The higher the frequency in general gives you more clarity and detail in the images, but you sacrifice the ability to penetrate deep water. So if you are chasing shallow water fish or mainly trolling for surface fish a H range will work well. But if you’re planning to go deep dropping in 300m+, consider the L.

– Transducer Power:
This is essentially a factor of cost. The more power you want, the more you will need to pay. You can get away with low power in shallower water, but many deep sea and game fishermen will appreciate some more power. Stock transducers are often around the 300-600W range. A good all rounder is 1kW. 3kW are awesome, but you will find they have a hefty price tag too.

How to set up your sounder:
Once you have got all all parts, its important you closely follow the manufacturers recommendation for installation. Especially with regards to the transducer. This is commonly where people have problems. For transom mount it’s easy to mount them too high or low and you will find you lose the bottom on the screen at speed. Double check this with the installation instructions if you are having problems, chances are it’s the transducer and not the settings of the sounder itself. You tend to find fewer installation issues with through hull as they are often done by professionals, but if you are having problems reading the bottom while motoring, check the angle of the transducer, check if its close to any hull features which may cause a disruption in water flow.

Once you are happy with the installation, it’s time to do a water test. In most cases, the auto gain and auto range modes will work quite well. So set it in these modes and motor to a known spot. While you are motoring, check that the bottom is reading clearly and there isn’t much noise on the screen. The noise will look like random spots on the screen. If you are getting noise, its probably a good idea to recheck the transducer installation.

At a know spot, slow down to around 3-5knt. You may see a momentary glitch on the screen, but that’s normal and usually caused by the auto mode changing settings. Give it a minute or so and you should start seeing a lot more clarity in the image. This is where you can start to familiarize yourself with what to look for on the screen.


A Samson fish school on a split screen in 120m depth

This article is still in development. We will post up some videos and photos to make it easier to work out what to look for.

If you have any special questions or requests, please let us know.