Locks in the Panama Canal provide a good experimental answer to the question: Can a battleship float in a bathtub?
In the excellent book, Thinking Physics, one question asks if a battleship can float in a bathtub. Ignore the obvious fact that no real bathtubs are as large as a battleship. The question is really about the amount of water required for a ship to float.
Very little water is really required. According to Archimedes's principle, the buoyant force on a ship or other object in water equals the weight of the water displaced. If the weight of the displaced water exceeds the ship's weight, the buoyant force is enough to float the ship. Ships weighing more than the displaced water sink.
Reading that statement might lead one to think that there must be at least enough water surrounding the ship to equal the weight of the ship, but that is not the case. The weight of the water displaced, not the weight of the water surrounding the ship, determines if the ship will float. The displaced water does not actually need to be there, hence there does not need to be much water actually surrounding the ship.
If there were a battleship-bathtub combination allowing the ship to just barely fit inside the tub, a thin layer of water between the outside of the battleship and the inside of the bathtub would be enough to float the battleship.
The locks in the Panama Canal are a good example of this principle. On a recent trip, I watched a ship going into the Miraflores locks of the canal. Even ships that barely fit into the locks float on the very small amount of water surrounding the ship in the lock. Observations confirm the theory.
Yes it is possible for a battleship to float in a bathtub.
