Kayak navigation light

In Australia, a kayak needs to have a white light that is visible 360 degrees around the boat. I looked at buying one, but at $160 that was enough to make me build my own from scratch. I started with a suitable LED. I found a 12V one on a well known ecommerce site that looked to do the trick. The 12V then drove the choice to use a 3S configuration of lithium ion cells (18650 cells) which I had lying around from a failed ryobi battery pack. I bought the 3S BMS to suit, already had a spot welder for the batteries so wired it all up and took dimensions for the battery case the bottom of which has a snug fit onto a piece of PVC pipe that my sister donated to me that she didn't need anymore. Then I designed the light cap and realised I should have a LED holder for the bulb, ordered one and waited for it to arrive so I could design the hole for it to fit into. Once I had the cap and the battery compartment I had too much wire to deal with so probably would be good to have a switch somewhere