A gallion is ignited on the high seas.

All sailors, except for the captain, leave aboard life boats.

The captain dives and swims under water for 90 metres. He hears an explosion.

When he surfaces, he immediately hears another explosion.

The captain rejoins a life boat and is pulled aboard by the sailors.

The captain mentions that he heard two explosions.
The sailors state that they only heard one explosion.
Both captain and sailors are telling the truth.

Question: How is this possible?

See answer