What does the term 'Francobordo' (Freeboard) designate, and what does a high freeboard provide to a small craft?

1. The distance between the propeller and the rudder, ensuring smooth water flow
2. The distance from the bottom of the keel to the seabed
3. The vertical distance from the waterline to the main deck, providing reserve buoyancy and seaworthiness
4. The width of the side decks allowing crew movement