While ultimately dismissed on jurisdictional issues the Sixth Circuit in In re: Nancy Buccina, et al., discussed the rule of The Pennsylvania, 86 U.S. 125 (1873) and the definition of a collision.
In this matter, the plaintiff was allegedly injured when the boat she was riding on hit a large wave. The district court found that The Pennsylvania rule, which puts the burden of proving that its violation of a statute prior regulation did not cause the injury on the ship-owner, did not apply. The Sixth Circuit, agreeing with the district court, held that the definition of collision was not so broad as to include a ship hitting a wave. Instead, a collision only occurs when two moving vessels strike one another.