Keels
I have a fin keel C22. When I faired my keel I generated and plotted my own profile using a NACA 0012 profile. A swing keel uses a shorter chord and I don't know the max thickness so recommending a profile without those parameters is impossible.The MK11 keel is SS reinforced fiberglass and lead. It is possible to retrofit but they cost almost $1000. If you just want to fair your existing keel I can give you some pointers. C22's have a horrible keel shape regardless of which keel you have. Your boat will sail faster and point higher if the keel is faired.