decided that I may do some dusk sailing this holiday and thought it would be best to have some nave lights just in case we do - bought a Navisafe three way (red/green/white) battery powered LED unit - pretty darn cool, has a magnetic base. I got some spare metal and made a removable piece to attached to forestay to mount the magnetic base.
So far so good, this unit plus a white LED for the stern should add some level of safety
I mounted the base well ahead of the forestay, and there is a lanyard you can attach to the stay or cleat in case it gets knocked off. The magnets are pretty darn strong, and the unit floats.
http://www.navisafe.com/
https://www.flickr.com/photos/124201309@N04/14552906502/in/photostream/
https://www.flickr.com/photos/124201309@N04/14530708126/in/photostream/
https://www.flickr.com/photos/124201309@N04/14573890643/in/photostream/