- Being lost at sea is a kind of being lost
- If a person is lost, then they need to travel to a location
- So, if a person is lost at sea, then they need to travel to a location

- If a person is lost at sea, then they need to travel to a location
- If a person needs to travel to a location, they need to direct themselves to that location
- Hence, if a person is lost at sea, they need to direct themselves to a location

- If a person is lost at sea, they need to direct themselves to a location
- The shore is a kind of location
- So, if a person is lost at sea, they need to direct themselves to the shore

- The shore is a kind of location
- If a person knows the cardinal direction of a location, and their own cardinal direction, then they can direct themselves to that location
- Hence, if a person knows the cardinal direction of the shore, and their own cardinal direction, then they can direct themselves to the shore

- If a person knows the cardinal direction of the shore, and their own cardinal direction, then they can direct themselves to the shore
- A compass is used for determining a person's cardinal direction
- Therefore, if a person knows the cardinal direction of the shore, and uses a compass to determine their cardinal direction, then they can direct themselves to the shore

- If a person knows the cardinal direction of the shore, and uses a compass to determine their cardinal direction, then they can direct themselves to the shore
- A magnetic compass is a kind of compass
- Hence, if a person knows the cardinal direction of the shore, and uses a magnetic compass to determine their cardinal direction, then they can direct themselves to the shore

- If a person is lost at sea, they need to direct themselves to the shore
- If a person knows the cardinal direction of the shore, and uses a magnetic compass to determine their cardinal direction, then they can direct themselves to the shore
- So, if a person is lost at sea, and shows the cardinal direction of the shore, then they can use a magnetic compass to direct themselves to the shore

Therefore, if a person is lost at sea, and shows the cardinal direction of the shore, then they can use a magnetic compass to direct themselves to the shore
Q: While a sailor was out fishing, he got lost at sea. Which object would help him direct the boat back to shore?
Context:
- If a person needs to travel to a location, they need to direct themselves to that location 
- The shore is a kind of location 
- A magnetic compass is a kind of compass 
- Being lost at sea is a kind of being lost 
- A compass is used for determining a person's cardinal direction 
- If a person is lost, then they need to travel to a location 
- If a person knows the cardinal direction of a location, and their own cardinal direction, then they can direct themselves to that location