## Facts

- A British steam propeller, *Pennsylvania*, collided on the high seas with the British sailing bark *Mary Troop* about 200 miles from Sandy Hook in a heavily traveled sea lane.
- A dense fog limited visibility to roughly 50 feet.
- *Mary Troop* was under way with sails set, moving at least about one mile per hour, and used a bell as its fog signal.
- A federal collision-prevention statute required: steamships under way to use a whistle; sailing ships under way to use a foghorn; and vessels not under way to use a bell.
- Although *Mary Troop* had a usable foghorn aboard, it was not used at the time of the collision.
- *Pennsylvania* proceeded at about seven knots in the dense fog and maintained lookouts; the bark was sighted only at close range, and the steamer struck the bark, cutting it in two and causing it to sink with loss of life.
- Owners of *Mary Troop* brought admiralty claims; the case reached the Supreme Court on appeal from the Southern District of New York.

## Issues

1. Whether *Pennsylvania* was at fault for proceeding at excessive speed in dense fog in a busy shipping track.
2. Whether *Mary Troop* was at fault for violating the statutory fog-signal rule by using a bell instead of a foghorn while under way.
3. What burden of proof applies when a vessel is in breach of a collision-prevention statute, and how damages are apportioned when both vessels are at fault.

## Decision

- The Court held both vessels at fault: *Pennsylvania* for excessive speed in dense fog, and *Mary Troop* for violating the statutory fog-signal requirement.
- The Court ruled that when a vessel is in “positive breach” of a collision-prevention statute, the violator must prove not merely that its fault probably did not contribute, but that it certainly did not and could not have contributed.
- Because both vessels were at fault, the Court ordered damages to be divided equally between them under the then-prevailing admiralty rule.

## Legal Principles

- A steam vessel must proceed at a safe speed in dense fog, especially in a well-traveled shipping route; excessive speed can constitute actionable fault in a collision.
- A sailing vessel under way in fog must comply with statutory fog-signal rules; using an unauthorized substitute signal constitutes statutory fault.
- When a vessel violates a statute intended to prevent collisions, the burden shifts to the violator to show the violation could not have been a contributing cause of the collision (the “Pennsylvania rule”).
- In a mutual-fault maritime collision, damages are equally divided between the vessels (as applied by the Court in this case).

## Conclusion

The Supreme Court found mutual fault in a fog collision and divided damages equally, while establishing a strict burden-shifting rule: a vessel that violates a collision-prevention statute must prove its statutory breach could not have contributed to the accident.


The Pennsylvania, 86 U.S. (19 Wall.) 125 (1873)