I found an old 17' length of 2x6, which really does measure a full 2" x 6", in the potting shed and figured it could be cut down and used to fashion the skeg. The fact that it is old and has numerous nails sticking out of it wasn't a concern - until today.
Those old nails (there are about 30 of them in the board) are not coming out of this old wood without a higher power of persuasion than I can muster. Cutting the nails out pretty much destroys the board - at least as far as using any part of it for the keg.
But, that cache of timbers I found a couple weeks ago is even better than I first thought. There are white oak 2x4s (actually measuring 1¾" x 4¼") ranging from 5' long to nearly 9' long. There are pine timbers, 1¾" x 4", and nearly 8' long. There are three 20' long 2x6 (not old, dimensional) boards (could be a mast in there…) Other shorter, pieces - some nearly 12" wide and better than an inch thick - may not be useful for Gardens but could certainly find new life in other projects.