I would have said "Illumination" but I was afraid you'd think I was getting esoteric on you. Actually I do that stuff in another Blog
Light is, weirdly, always an issue on a boat. It's odd since they tend to be such compact spaces, but often windows are weirdly placed and power can be an issue. A 100 watt bulb will easily light up a cabin, but it will also heat it like an ezbake oven and exhaust even the most robust batteries quickly.
Going into Floating Empire, we relied largely on magnetic, LED battery lights. This was a really good idea for spot illumination. Any metal surface could be an anchor for the lights, and the simple addition of a bit of metal stripping or even a fender washer can create an attachment point.
We also put up a few strategic hooks for operating either LED battery lights. . .