Bava Batra 75 - Acquiring a Ship

What proprietary act effects the acquisition of a ship? Rav says, "Once the buyer has pulled the ship even a small distance, he has acquired it." But Shmuel says, "He has not acquired the ship until he pulls it away completely away from the place it originally occupied."

Is this the same disagreement as the two views on acquiring an animal by pulling: (1) the animal is acquired when it raises the front and hind leg, or (2) only when it walks the full length?

No, it is not the same! Once the animal starts to move, it will move the other two legs, but the ship may stop after the initial push. On the other hand, once a ship is moved, it moves as a whole, whereas an animal can put its legs back. The two disagreements are different, and both had to be recorded.