Hi Marty, we do LED's on boats weekly. Under gunwale, spreader, interior, underwater, etc. Just give me a call and I can help you pick out whatever you need.
The caprera lights mentioned above are nice for spreaders but are metal. We all know what powdercoated metal looks like on a boat after a few years. They can't make theirs out of modern plastic because it would get too hot. We brought in a new technology that enables us to provide the same amount of light but hardly generate any heat. So ours are the first plastic spreader lights that will last a long time in the marine environment. Plus they have a bunch of other bullet points that other light manufacturers haven't even thought of yet. Like the ball mounting system, interchangable lense system and more.
You can see a brightness comparison at
www.lunarledlights.com