Compound Pulley Systems and Z-Rig Mechanical Advantage Quiz

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30 Questions

A bight is formed when a rope crosses over itself.

False

The standing part of a rope is the section that threads through to complete the knot.

False

Safety knots are primarily used to increase the strength of the rope.

False

A bend connects the free end of two ropes together.

False

All knots increase the strength of the rope.

False

A loop is a turn of rope that does not cross itself.

False

To test the system, the stretcher should be lifted up to a vertical position and the patient should not drop during the process.

True

The Furley Stretcher Tie-In is a method used to connect a casualty securely to a Furley stretcher.

False

High forces are rarely encountered during rope rescue operations.

False

It is not necessary to assess the strength of an anchor when planning a rescue operation.

False

To reduce leverage on a vertical anchor, it is recommended to secure the anchor attachment far from the ground.

False

Building a bridle anchor from two anchor points is unnecessary when anchors are not in line with the rescue.

False

If the distance between a highpoint COD and the ground is high enough to cause harm, then the rigging should be run at ground level.

True

Most rescues can be accomplished with an 8:1 pulley system.

False

A prusik will slip at around 300 kg (660 lbs).

False

Rescuers need to calculate the force that will be exerted by the MAs before using a pulley system.

True

Belaying is primarily used for rigging purposes in rescue operations.

False

Using a COD is essential in situations where the main anchor point aligns perfectly with the load.

False

In a compound pulley system with different MAs, it is recommended to attach the system with a higher MA to the load.

False

A Z-Rig MA is a 4:1 MA made with a single rope.

False

Complex MA systems require more equipment compared to simple MA systems.

False

A change of direction (COD) within a MA occurs when the pulling force on the rope end is traveling in the same direction as the load travel.

False

A Z-Rig gets its name from the shape it forms when deconstructed.

False

Ideally, separate anchors for each Mechanical Advantage (MA) should be less than a meter apart.

False

Munter Belay techniques are suitable for high-structural or cliff rescues.

False

A safety belay system never comes under tension unless there has been a failure in the main line.

True

A whistle test is used to ensure that the safety belay system can withstand catastrophic events.

False

For mine rescue rope rigging, it is recommended to have only one independent rope system as a back-up.

False

Munter Belay techniques are quick to set up in situations where immediate first aid is needed.

True

Safety Belay Systems are designed to fail in case of equipment failure or human error in the main line.

False

Study Notes

Knots, Bends, and Hitches

  • Rescuers must be able to tie knots, bends, and hitches in all conditions
  • Key factors to consider when choosing a knot:
    • Proven safety for intended use
    • Sufficient strength for its role
    • Easy to tie and untie
    • Does not affect system strength beyond acceptable safety factor

Types of Knots

  • Knot: a connection method used in rope or webbing to tie it to itself
  • Bend: a tie that connects the ends of two ropes or webbing together
  • Hitch: a tie that attaches a rope or webbing to another object
  • Bight: an open turn formed when a rope is doubled back upon itself
  • Standing part: the inactive section of rope during the process of tying a knot
  • Running end: the end of rope that threads through to complete the knot
  • Loop: a turn of rope that crosses itself
  • Tail: the free end of rope that extends from a knot

Safety Knots and Stretcher Tie-In

  • Safety knots are used to prevent fraying and to stop from sliding through a block, hole, or other knot
  • Example of a stretcher tie-in: Furley Stretcher Tie-In, which securely lashes a casualty to a furley stretcher

Anchors

  • Anchors must be solid and unmovable relative to the load being applied ("bombproof")
  • Two or more anchors should be incorporated into the system whenever possible to minimize leverage
  • Critical angle: when anchors are not in line with the rescue, a bridle anchor from two anchor points is necessary
  • Anchor leverage: securing the anchor attachment close to the ground reduces leverage on a vertical anchor

Mechanical Advantage Systems

  • Z-Rig: a 3:1 mechanical advantage system made with a single rope that can be easily changed to a higher MA
  • Complex MA systems: combining two simple MA systems to accomplish a larger MA with less equipment
  • Change of Direction (COD): where the pulling force on the rope end is traveling in the opposite direction of the load travel
  • COD is needed in situations with limited space, misaligned haul lines, embankment-type rescues, and cliff rescues

Large Mechanical Advantage Systems

  • 6:1 pulley system can accomplish most rescues
  • 8:1 and 9:1 systems are not recommended due to rope and space requirements
  • Safe working loads of rigging equipment must be considered in terms of force applied by these larger MAs
  • Rescuer Pulling Force: the average rescuer can pull with a maximum force of 23 kg (55 lbs)

Belaying

  • Belaying is used to protect a person or load from falling
  • Munter Belay techniques can be used for a single person safety line on low-angle consolidated slope
  • Safety belay systems:
    • Catches the load of the main line if it fails without an operator to engage it
    • Must be able to survive the event sufficiently undamaged and allow load to move up or down

Test your knowledge on resetting compound pulley systems with different mechanical advantages and using Z-Rig mechanical advantage systems in rope rescue scenarios. Learn about best practices for attaching and pulling loads with varying mechanical advantages.

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