I use to use 1157 tail light brake light bulbs, i would wire them so both elements would burn made a bracket out of pcv pipe that fit over the front of a 13 foot Boston Whaler and they hung down about 3 foot deep....coarse this was 25 years ago...put them in the water before we turned them on, they worked really well for what we where doing...we where gigging and the shallow canals and poling the boat.