I saw a documentary YouTube video recently and it said that there is a small amount of deterioration on the boat deck near the bridge. As for the ship itself as it is covered in coral the steel is not deteriorating as badly as on Titanic. I expect it remain intact for many decades to come. The boilers and engines will eventually collapse inside as they are still holding in place on a ship that's on it's side. This will probably cause massive damage and cause the ship to collapse quicker.