If you're planning to operate a kayak at night, the traditional red/green bow lights are a REALLY BAD idea. Kayaks are slow moving craft, so lighting one to powerboat requirements could get you run down by someone thinking you have manueverability and speed.
Go with a traditional white light visible from 360 degrees. powerboaters recognize the fixed white light as a vessel at anchor and should steer clear.
Here's my favorite, made by kayakers for kayakers. The VISIPole from YakAttack