Since Sky appears to be the only owner of the same model that sank, who is on the Forum, he's a valuable resource. And, since he is convinced the sponson is not required for flotation, and pretty much the rest of the TF believes it is (I can't recall seeing a hollow, watertight outboard brackets, call it a sponson if you will, that didn't provide buoyancy, never the less, in the interest of pursuing the scientific method...), perhaps Sky would be willing to fill his sponson with water as a controlled test. If, during the filling, the waterline sinks below the float line, and the cockpit drains stop draining, that would be definitive. If this were the case, even an otherwise self-baling cockpit could be overwhelmed as they are designed to remain above the WL.
Another consideration, and if it's been mentioned my apologies for missing it, the vessel in question sank on a fresh water lake. A vessel's buoyancy in fresh water is reduced, which would have caused it to float lower in the water, which in turn may have affected drainage or allowed water to find an ingress point that would otherwise be higher and not vulnerable. It would be interesting to know if the builder took this into consideration during the design and testing of the model. This may be why the issue has not reared its head on other similar models that are used primarily in saltwater.
I still don't believe all the facts are in evidence, however, we are fortunate to have a participant who has the same model in the discussion, let's keep him engaged. And, there can be a happy ending, at least for TF participants, if a sinking like this one is avoided, or if the buyer of a new boat, after reading this thread, decides to have it surveyed before closing the deal.
Another suggestion, keep the emotion and unfounded accusations out of the analysis, it only discourages those with a dissenting opinions from contributing.
