Here in Western New York, the primary concern is not getting run over by power boats. We all use the Kayalu deck light. It accomplishes 3 important things. 1. Can be seen from miles away yet does not blind other yakers. 2. When mounted on the rear deck it is elevated and can be seen 360 degrees even in swells. 3. The mounting makes it nearly indestructible and you can even roll with it. Remember, flashing means distress and headlamps are directional and blinding to others, And can’t be seen from the rear.
Recent article, “Being Seen at Night”, misquoted USCG Navigation Rules, and says lights on a kayak at night are not required, but a white light “can” be carried. Rule 25(d)(i) says a vessel “under oars” (which includes kayaks, paddleboards and canoes) may carry same lights as a sailboat, “but if she does not, she shall exhibit an all-round white light or have [one] ready at hand”. “Shall” means mandatory. Be aware that bright lights on shore and docks can obscure small lights and destroy the night vision of other operators. A few pieces of retroreflective white tape on the paddle blades attract notice and help identify the craft.
I use a Kayalu Kayalite mounted with a Scotty base and PVC extension that holds it 36"+ above the stern deck. It keeps me on good terms with the Marine Patrol while paddling the backchannels and the mouth of the Piscataqua River in New Castle, NH.
I use white Adventure Lights Guardian expedition lights one on my rear deck and one on the shoulder of my PFD they are waterproof and can be seen for a fair distance these can also be set to constantly flash just by flipping the battery around. For an emergency light I picked up one of those small black aluminum LED flashlights they are waterproof and very bright and you can get one that will continually signal an SOS I have seen them on Amazon. I also use a regular headlight to aid visibility.
https://www.amazon.com/gp/product/B00VX0JW9Q/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
$25
works great, mine has spent time in the water. I use mine for sunset/moon rise paddles.