A broken/worn skeg can easily be replaced. When I bought my 1988 115 HP Merc in 2010, the skeg was broken because the owners forgot to lift the motor backing out of the driveway. My prop man selected from his stock of skegs and blended the new skeg into the old using a zigzag cut for strength. Cost was very reasonable. While I was at it , I sharpened the leading edge of the lower unit and had it painted.