Check your sensitivity setting for the SI screen. If you set it to auto it will vary the screen brightness along with the sensitivity setting going up or down depending on the depth of the water and the range you have it setup for.
Try manually setting the sensitivity up to about 20 to see how bright the screen gets at the max sensitivity setting. Then set it back down to around 3 or 2 and note the difference.
If you know the lake you are fishing you may be able to just set the settings manually and set them up higher.
I have a raptor shield on my unit too and it does help some. But these screen can still be hard to see in bright sunlight. I plan on putting an umbrella over my seat where the unit is located to shade it even more so that I can see the screen better.
And Polarized sunglasses blocks out a lot of the light rays. Any polarized light that's in the vertical and that's bouncing off a reflective surface will be blocked out by the polarized sunglasses. But the light that's polarized at 90 Deg to that blocked light will get through the sunglasses.
Light is polarized by the reflecting surface and at right angles to the light rays line of travel.
Thanks I just ordered a raptor cap.
Jorawil