Scott Rall: A closer look at what's under the water

BY SCOTT RALL The Globe outdoors columnist I have an older iPhone. I think it is a 6. They have had many updates on my phone since it was purchased. They have bigger screens and better functions. When it comes to electronic and tech stuff, I stil...


The Globe outdoors columnist

I have an older iPhone. I think it is a 6. They have had many updates on my phone since it was purchased. They have bigger screens and better functions.

When it comes to electronic and tech stuff, I still live in the stone age. I was having trouble the other day trying to get one person in my phone book into the favorites section.  

I needed the help of others. In many cases, that can easily be a 10-12-year-old. I, for all practical purposes, have given up on being tech savvy. I can get by, but just barely.


I am in currently in kind of a tough tech spot. I got invited on a fishing trip next September to Rainy Lake. The inviter told me all I needed to bring was my boat and some fishing electronics that had the Rainy Lake chip in it. I know what a chip is, but that is about the limit of my tech fishing electronics savvy.

Fish finders today are so much more than fish sonar. The first fish finder I bought back in 1975 was called a Lowrance Green Box. Fish sonar at that time was really used to tell how deep the water was and not much more.

The unit sent a pulse down to the lake bottom and measured the time it took to bounce back to the top. It then calculated the depth. These were pretty crude units by today’s standards, but it was a major breakthrough back then.

A basic fish finder today, even the cheap ones, have GPS and detailed looks at the underwater world. The invention of GPS, which stands for Global Positioning System, allows me to mark a spot in the middle of the ocean and return to that exact spot later to a margin of about six feet.

So, when a fisherman finds a spot in the middle of the lake that holds fish, they can mark that spot and return over and over.  This has changed the fishing world a lot.

The unit I am considering is far more advanced than anything I have ever used before. These combination GPS and fish sonar have a memory large enough to store lake maps for almost every lake in North America.

In other cases, you buy a chip that is inserted into the unit, which stores the lake data for specific geographical areas. You can buy a Canada chip or a Florida chip and everything in between.

One of the most important features of these new fancy units is that they also show you a color-coded underwater topographical map.


Water that is under five feet deep is one color on the screen. Water that is 5-10 feet deep is a different color. In many lakes, the water depth can change from 60 feet to three feet deep in as little as 20 yards. Running a boat at 35 miles per hour is very dangerous in these waters if you don’t know for sure exactly how deep the water is.  

The map allows the boat operator to travel at very fast speeds between fishing spots because they can tell exactly how deep the water under the boat is.

Fish sonar today does not just look under the boat. They have side scanning capability to look for fish out to the sides of the boat as well.

You might see a bunch of big boulders out to the side of the boat that the down scan would not see. This allows you to GPS mark that spot and turn around and go toss a few casts there.

Fish sonar today can see fish lying flat on the bottom. If the fish are off the bottom even a few inches, you can literally count the number of fish under the boat. It is this clear picture of what is below you and out to the sides of you that have made anglers much more successful.

Units with the underwater topography maps can even be integrated to the electric trolling motor so that the motor automatically follows and steers to keep the boat at 12 feet deep.

Truly unbelievable advancements have been made. They have what’s called the electric anchor. You can push a button and the GPS and the motor will work together to keep you hovering over a spot just like a helicopter would.

The only limiting factor in the search for a new GPS/Fish sonar is funding. The units can cost as little as $300, like the one currently on my boat, all the way up to $3,000 or even more. The more you spend, the more features you get and the bigger the screen you get to look at.


I have a friend who is very tech savvy when it comes to fishing electronics, and my next purchase will be on in the middle to lower end of the scale as long as it has the right lake maps in it.

I will buy what he tells me to. This guy has probably purchased 25 of these units over the past 25 years. He is the expert, and I am the novice.

A trip to rainy lake in September is going to be great. Hopefully I will have figured out to run my new fish sonar by then.

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