I did add LEDs under the gunnels for deck lighting for night fishing.
I was looking to do the same thing for the same reason. What color and how many LED's did you go with? I will be adding them to a 20' Walk.
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Just a caution here!

I installed 2 strings of "outdoor" LED lights that I purchased on-line and were promoted as being a marine product. These had 2 LEDs in small chrome plated, self adhesive, ovals about 6 inches apart. I had a short as the housings either aren't sealed well or corroded from the salt environment. Fortunately, these were CB protected and a more serious situation was avoided.
I removed these after that experience. Don't go cheap. Buy lights that are designed for the marine environment.