to be under hatches

Hatch \Hatch\, n. [OE. hacche, AS. h[ae]c, cf. haca the bar of a
   door, D. hek gate, Sw. h[aum]ck coop, rack, Dan. hekke
   manger, rack. Prob. akin to E. hook, and first used of
   something made of pieces fastened together. Cf. {Heck},
   {Hack} a frame.]
   1. A door with an opening over it; a half door, sometimes set
      with spikes on the upper edge.
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            In at the window, or else o'er the hatch. --Shak.
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   2. A frame or weir in a river, for catching fish.
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   3. A flood gate; a sluice gate. --Ainsworth.
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   4. A bedstead. [Scot.] --Sir W. Scott.
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   5. An opening in the deck of a vessel or floor of a warehouse
      which serves as a passageway or hoistway; a hatchway;
      also; a cover or door, or one of the covers used in
      closing such an opening.
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   6. (Mining) An opening into, or in search of, a mine.
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   {Booby hatch}, {Buttery hatch}, {Companion hatch}, etc. See
      under {Booby}, {Buttery}, etc.

   {To batten down the hatches} (Naut.), to lay tarpaulins over
      them, and secure them with battens.

   {To be under hatches}, to be confined below in a vessel; to
      be under arrest, or in slavery, distress, etc.
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