If each anchor moves you down one unit and each float moves you up one unit, then we have the following situations:
1. In the first square we have 2 anchors and 1 float. That means that we should have moved 2 units down because of the anchors and then 1 unit up, therefore, we should be one unit beneath sea level. Therefore the image is correct.
2. The square to the right of the previous show two anchors and two floats, which means that we moved down two units and up to two units, therefore, we must be at sea level, therefore, the image is correct.
3 The first square at the bottom shows two anchors and one float. This is the same situation as 1. therefore the image is incorrect since the boat should be one unit beneath sea level.
4. The last square shows the same situation as 2. Therefore the image is wrong as it should be at sea level.