I am in agreement with Mihun09's method. Another method was to use a combination of boiled linseed oil, mineral spirits, and wood preservative applied heated to the outside before canvasing. Linseed oil is excellent food for mold but since the old canvas filler was made with white lead, its toxcicity, along with the old formula Cupernol, kept the mold under control. I too will be interested in Memequay's experiment. My concern is not with the flexibility of epoxy, but rather with, as Canotrouge stated, the bonding of the ribs to the planking. Even a mild contact with a rock may result in broken ribs and/or planking.
Dave