As an alternative to expensive thru hull/surface mounted underwater lights when we do a canyon trip I use lights by brinkman
Q-beam 12 Volt Underwater Light Underwater fishing light for bait making or attracting your favorite species! Brinkmann lights have made my bait catching experiences easy and quick for squid, mackerel and other bait needed ......... - 2catchfish.com
I cut the end off and put a plug in adapter instead of alligator clips. I installed a pair of 12v adapters in the cockpit and hang one of these over each side. At approx. $25 they throw a lot of light. I know it would be nice to have the lights below the water but these work fine for us.