Solution: Yes, a compass can be used in a submarine. It is not much different than a ship fir a compass. As the magnetic field is a slowly-varying field, it will not be fully shielded by the hull.

Why compass does not work in submarine?

The body of a submarine is made of magnetic material like iron and steel. This acts as a shield to the earth's magnetic field. That means, earth's magnetic field will not be able to influence the magnetic compass correctly within the submarine.

Can you use a compass underground?

The short answer is yes, a compass will work underground — but also: a nearby iron deposit can throw a compass off track. This problem is not just limited to caves. Compasses can also be affected by large steel structures above ground.