A ladder is a vertical or inclined set of rungs or steps. There are two types: rigid ladders that are self-supporting or that may be leaned against a vertical surface such as a wall, and rollable ladders, such as those made of rope or aluminum, that may be hung from the top. The vertical members of a rigid ladder are called stringers or rails (US) or stiles (UK). Rigid ladders are usually portable, but some types are permanently fixed to a structure, building, or equipment. They are commonly made of metal, wood, or fiberglass, but they have been known to be made of tough plastic.

 

Rigid ladders.

  • The accommodation ladder is portable steps down the side of a ship for boarding.
  • Assault ladder, used in siege warfare to assist in climbing walls and crossing moats.
  • Attic ladder, pulled down from the ceiling to allow access to an attic or loft.
  • Bridge ladder, a ladder laid horizontally to act as a passage between two points separated by a drop.
  • Boarding ladder, a ladder used to climb onto a vehicle. Maybe rigid or flexible, also boarding step(s), and swim ladder
  • Cat ladder (US chicken ladder), a lightweight ladder frame used on steep roofs to prevent workers from sliding.
  • Christmas tree ladder, a type of boarding ladder for divers that has a single central rail and is open at the sides to allow the diver to climb the ladder while wearing swimfins.[1]
  • Counterbalanced ladder, a fixed ladder with a lower sliding part. A system of counterweights is used to let the lower sliding part descend gently when released.

     Flexible ladders.

      Rope ladders or Jacob’s ladders are used where storage space is extremely limited, weight must be kept to a minimum, or in instances where the object to be climbed is too curved to use a rigid ladder. They may have rigid or flexible rungs. Climbing a rope ladder requires more skill than climbing a rigid ladder because the ladder tends to swing like a pendulum. Jacob’s ladders used on a ship are used mostly for emergencies or for temporary access to the side of a ship. Steel and aluminum wire ladders are sometimes used in vertical caving, having developed from rope ladders with wooden rungs. Flexible ladders are also sometimes used as swim ladders on boats.