For a submersible light for night fishing, I bought five or six green chemical lightsticks. Each stick has a plastic grommet on one end. I strung the sticks on a stout line with a two-ounce weight to sink them to the right depth and tied them in a loop to keep them together. When I'm ready to fish, I simply snap each stick to activate the chemical reaction and hang them off a stern cleat at the appropriate depth. Baitfish in the area are attracted to the light, and they in turn attract the bigger fish - the ones I want to catch.