Hi Peter,
My one example is OK but I have to make sure I don't do wave catching launches from sandy surf beaches! Sand [crunched up shells] gets jammed in the slot.I now put it in the water first but usually get soaked in the spume before getting my spray skirt on.All good apart from that.If you go for the dagger board let us know how it goes,please.
http://www.kayakforum.com/cgi-bin/Building/index.cgi/page/4/md/read/id/222435/sbj/strip-a-skeg-story-and-a-good-solution-maybe/