Prepare for trouble.
Batten down the hatches, In his recent (September 2012) song Tempest, which recounts the story of the Titanic’s sinking, Bob Dylan uses the lines:
They battened down the hatches
But the hatches wouldn’t hold
This has caused a couple of correspondents to write to me asking what ‘batten down’ means. Many people may know what ‘batten down the hatches’ means, but some clearly don’t, so here goes…
‘Hatch’ is one of those words with dozens of meanings in the dictionary. In this case we are looking at the ‘opening in the deck of a ship’ meaning. Ships’ hatches, more formally called hatchways, were commonplace on sailing ships and were normally either open or covered with a wooden grating to allow for ventilation of the lower decks. When bad weather was imminent, the hatches were covered with tarpaulin and the covering was edged with wooden strips, known as battens, to prevent it from blowing off. Not surprisingly, sailors called this ‘battening down’. – http://www.phrases.org.uk/meanings/batten-down-the-hatches.html