#keel  one of the main longitudinal beams (or plates) of the hull of a vessel; can extend vertically into the water to provide lateral stability
  supertype:  beam  long thick piece of wood or metal or concrete, etc., used in construction
  subtype:  bilge_keel  either of two lengthwise fins attached along the outside of a ship's bilge; reduces rolling
  part:  fin_keel
  part of:  hull  the frame or body of ship
     part of:  vessel.craft__watercraft  a craft designed for water transportation

No statement uses or specializes keel; click here to add one.