How do you use the side view of a fishfinder to locate and mark an underwater structure?

Side Imaging view of a submerged bridge.

The side view on a fishfinder is a tool that makes prospecting much easier. It's easy to use and allows you to mark structures directly so you can adjust your drifts to optimize your fishing.

Prospecting and discovering new areas is a very interesting part of sea or freshwater fishing. Fishing little frequented areas is to increase your chances of finding beautiful fish not used to the presence of fishermen.

The submerged structures are ideal shelters for fish. A whole ecosystem is formed around it. For predators, it is a guarantee to have both food and a relatively safe place to shelter.

Whether in the sea or in fresh water, some structures are easily spotted or known by many people. The fishing pressure is strong, the fish are very solicited and the beautiful catches, either in size or in quantity, are rare. Prospecting will allow you to discover new ones which are either not listed or with an approximate location.

The side view, the perfect tool!

In this case, we will see how to proceed to locate a wreck from an approximate position. Obviously, the procedure will be the same in fresh water.

First, you must locate it and then mark it on the GPS so you can fish it again. To do this, you must be equipped with a fishfinder with the side-view technique. It has different names depending on the brand of your device:

This view allows you to detect underwater structures from the side.

Une vue latérale sur laquelle il est possible devoir un arbre immergé" ainsi que des blocs rocheux. Autant d'abris potentiels pour les poissons prédateurs.
A side view on which it is possible to see a submerged tree as well as boulders. So many potential shelters for predatory fish.

How to proceed?

  • The first step consists in passing as close as possible to the structure, with the engine engaged, at reduced speed (less than 5 knots).

On your sonar unit, set your scale so that it is equal to about 3 times the depth. In our case, with a depth of 25 meters, a scale of 75 meters on either side would be sufficient.

You will then see the structure appear, here the wreck! Create two waypoints, one for the bow (front of the boat) and one for the stern (back of the boat). This will allow you to better visualize the orientation of the wreck.

Repérez l'épave ou la structure sous-marine et maquez la de plusieurs waypoints
Locate the wreck or underwater structure and mark it with several waypoints.
Remontez en amont de la dérive en évitant de passer directement sur la structure puis laissez vous dériver, moteur éteint, sur celle-ci.
Go upstream of the daggerboard, avoiding going directly over the structure, and then let yourself drift over it with the engine off.

Next, you can switch your sonar to 2D or FishReveal as shown in the image below to better view fish detections.

Détection de lieus jaunes sur une épave repérée grâce à la détection latérale.
Detection of yellow lees on a wreck located by lateral detection.
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