My understanding is teak glued to plywood, the screws were to hold the teak in place while the glue cured. The screws are what causes the leaking through the deck. Remove the teak plugs, remove the screws, drill a hole a bit bigger then the screw hole, fill with epoxy and new plugs will fix that problem, is what I read to remedy the problem. We are going to give that a go once the spring rain here in Poulsbo subsides some.