Complex sentence: The initial operation, using "chariots" (manned torpedoes), fails and the crew are forced to abandon ship and land in Norway, walking to neutral Sweden, from where they are returned to Scotland.
Split into simpler sentences: The initial operation, using "chariots" (manned torpedoes), fails and the crew are forced to abandon ship and land in Norway. They walk to neutral Sweden, from where they are returned to Scotland.