Ran into this DIY today, others may have already. I think it would be useful to some looking for a kayak light and referencing the conversations about visibility out of boca and other inlets. Lights that cover the entire vertical water column and something thats INEXPENSIVE. Some of these yak companies suck the life blood out of simple things and sometimes the lights sold are 1/4 of the cost of a kayak itself.
Ultimately nothing replaces a competent boat captain.