A) Replacing and installing a skeg is relatively easy following these 7 steps. See attached file for steps and pictures:
1) Feed the spectra skeg line through while tubing from the skeg box towards the skeg dial and it appears. Keep a few inches at the skeg box end loose.
2) Prepare skeg box kit with two sides, the blade, pin and cord. Feed the cord from one side through the lower hold of the skeg and attach to the other side and make a knot at each end.
3) Attach the skeg assembly with the four bolts and washers.
4) Attach the skeg line to the 2nd hole on the blade and make a knot (bowline is best)
5) Hold the blade in the box in place with tape
6) Pull the excess line at the skeg dial end until tight. Then assemble the skeg dial by feeding the line through bottom of dial. Then insert dial into bolt hole. Attach nylon washer, stainless steel washer and nylon lockwasher and tighten.
7) With dial set to 0.5 mark, make a knot around 2nd screw/bolt then tighten.
B) Replacing the bungee cord at skeg end will need 4mm*length 12cm. and the length of the cord on both sides of the skeg kept 4cm long is fine.