[tsubaki]

I seen one guy in the neighborhood hoist the bow straight up to let it drain for a year with moderate results.
After finishing another boat project that had a foam filled bottom we came to the conclusion that it would be impossible to drain all the water out unless during the manufacturing process to make a channel down the keel and wick channels to that between the stringers.
Unless they have changed designs water will inherently stay trapped between the stringers.