Navigation Lights by Lopolight, Attwood and others
All vessels are required to carry navigation lights at night to indicate heading, size and activity as part of a comprehensive scheme of collision avoidance rules established over 100 years ago.
Wikipedia discusses broad requirements, and the US Coast Guard has a detailed website relevant to all vessels, large and small, sail or powered.
Attwood Navigation Lights include lights suitable for both in-shore and off-shore boating, with versions suitable for fixing on contoured decks and with a quick-release system so that lights can be stored securely when not in use.
Lopolight use innovative high-luminance LED technology, with an extremely-long service life.
Navisafe also use high-intensity LEDs. Their lights are portable and can be mounted magnetically. Ideal for all sorts of recreational purposes, not just navigation lights. Double magnetic holders are available to permit mounting on non-magnetic surfaces. Even a hat!