I installed under gunwale LED lights on my 23SE, but I did not need to drill any holes. The LED strips came with double sided tape already attached, so I just stuck them underneath the gunwale. In between each strip I have an adhesive piece of plastic used to connect zip ties to, which I used to fasten the slack in the wires. I don't know their technical name, but in Home Depot they are sold along side the zip ties.
I have pics with the lights turned on, but I do not have any pics of the install to help explain and I won't be back at the boat until Father's day weekend.
They look and work awesome. I have red to maintain night vision and white for when I want brightness.
Gary