For paddling or rowing at dusk, or at night,
www.topkayaker.com at 1805 Rt-16 in Center Ossipee NH has a number of high quality, battery powered l.e.d. navigation lights which show brighter than the old incandescent bulb lights. In the Safety Gear section...
For a kayak or stand up paddle board, a bright white l.e.d. navigation light can maybe make the difference between being seen, or becoming a "speed bump."
For $19.99 check out the 'c-strobe with c-clip' that's powered by two AA batteries, not included, and flashes with 45-lumens white light ..... hand held ... you can wave it around and pray you don't get hit ....... or attach it to your pfd ..... does not float .... "has intense strobe light visible up to 2-miles."
www.topkayaker.net