Spot lights in boats are NOT like headlights on cars. Please don’t try to use them as such. You will blind yourself and ruin other boater’s night vision. Spotlights are intended to be used briefly for picking out or confirming the location of objects like a nav aid, other (moored) boat, or a dock. Otherwise it’s much more effective to use your night vision. You will actually see far more and have better situational awareness by just letting your eyes adjust to the dark. Save the light for picking out the nav bouys. A hand held light is often more versatile and useful than a fixed light.