Have you had any water intrusion issues under the floor? if so has it ever caused any other damage? wet core etc?
Yes, I have had water under the cabin floor and the cockpit floor.
I had minimal core damage in the cabin floor mostly caused by the screw penetrations of the L brackets that hold down the plywood cabinet dividers and the water tank frame. Thanks to this site, I learned how to repair these - over-drilling holes, routing out the balsa, re-filling with epoxy, then using fiberglass fillets to re-attach the dividers and water tank frame.
I have mostly solved the water-under-the-floor issue by re-sealing the joint between the cockpit floor and the cabin bulkhead, removing and glassing in the factory foam injection holes located on the cockpit deck and also on the cabin bulkhead just below the door. They were originally "plugged" with the plastic plugs from the factory.
I have also removed the windlass, V-berth hatch, and the 2 aft sponson covers and re-installed. (Replaced the 2 aft covers). The worst damage was under the anchor windlass and the V-berth hatch, the damage extended to about 2-3 inches horizontally. Now filled with thickened epoxy.
Oh, and also cut an inspection port in the floor of the cabin near the door so I could keep an eye on the issue. So far (fingers crossed), no more water other than condensation.