I have installed a retractible skeg ( after deck installation) on my Ches.17, and I find it very functional especially when traveling down wind in front of a good surf. I don't have to struggle with corrective strokes as often, and the boat tracks considerably better than without the skeg. It is nice also when ferrying across an expanse against a wind. The down side is that I can't make quick corective strokes as the boat does not turn well with the skeg deployed. I also have found that the boat generally tracks well (better than my Cape Charles 17 which will benefit even more from a skeg I plan to install) and can be corrected by stroking and leaning, but the skeg really helps in certain conditions. CLC has plans that are a good starting point. You will definitely have an easier time before the deck goes on. In retrospect, I would like to modify the design so that no part of the skeg or mechanisms protrude through the deck.