The video below details the installation of a centerboard control line. However, the video is missing the first step in replacing a line - which is to tie off the 3/8" line to the padeye on the front of the centerboard. To get access to this padeye with the boat in the water, simply use a long stick to push down on the back of the board from within the boat (with the inspection cap removed). With the board pushed down as far as it will go, tie a couple of half-hitch knots to the accessible padeye and continue on where the video starts.
For better access, remove all the bolts which include the top case tensioning bolt, the clutch bolt, and bottom guide bolt.
Take care when tapping out the two pins that extend through the clutch and clutch bolt - be careful not to drop them down between the board and the case.
Other than that - watch the video for a step-by-step on installing a new centerboard line. Questions? 410.626.2720