Haven't posted in a while and noticed your comment. It is fundamentally accurate, but the deck load diminishes linearly as a function of distance from the deck to the inside of the hull bottom. This is why you see a lessening level of adhesive wear on the tube going downward. Therefore, in this case it is best to reinforce probably 4 to 6" below the deck in order to make sure that transition area is structurally sound; because you can't phool physics.The main purpose of the tube from below the deck to just above the plywood base is to keep water out. The load from the mast is handled at the deck and plywood base. So if you don't have cracking/delam/core failure on the deck, the repair is is mainly to just get the tube watertight again.
Haven't posted in a while and noticed your comment. It is fundamentally accurate, but the deck load diminishes linearly as a function of distance from the deck to the inside of the hull bottom. This is why you see a lessening level of adhesive wear on the tube going downward. Therefore, in this case it is best to reinforce probably 4 to 6" below the deck in order to make sure that transition area is structurally sound; because you can't phool physics.
If i'm not wrong the fact that the vang has no connection to the hull should mean that it doesn't add to the forces on the wooden block.The bending force above the tube is the vang and the main sheet.