Mech Advantage

Question 1

What are the three categories of MAs

Answer 1

• Simple
• Compound
• Complex

Question 2

How do you determine if the MA is odd or Even

Answer 2

If the MA starts at the load, its ODD

If the MA starts at the anchor, its EVEN

Question 3

Define a “simple” MA system

Answer 3

A simple MA system consists of a single haul connection between the load and the haul team

Question 4

Define a “compound” MA system

Answer 4

A compound MA consists of a simple MA pulling on the haul line of another simple MA

Question 5

Define a “complex” MA system

Answer 5

A complex MA is neither a simple, nor a compound MA.

It will also incorporate “floating” pulleys that move toward each other as the system is put in motion

Question 6

Define a “integral” MA system

Answer 6

An MA system that consists of a single rope

Question 7

Define a “Ganged On” MA system

Answer 7

An MA system that is built separate from the working line with a second rope, and is attached to the mainline by a haul prussik

Question 8

Define a “pig rig” MA

Answer 8

A pig rig is a compound MA system that is made up of two identical simple MAs that is then ganged on the mainline.

Question 9

Define a Change of Direction Pulley

Answer 9

A c.o.d. pulley is is a pulley that is attached to the anchor and is last pulley before the haul team.

Question 10

Define “IMA” or Ideal Mechanical Advantage

Answer 10

The IMA is the ratio between the input and the output of an MA in an ideal world with 100% efficiencies

Question 11

Define “PMA” or Practical Mechanical Advantage

Answer 11

The PMA is the ratio between the input and the output of an MA with efficiency losses from pulleys or carabiners calculated.

Question 12

What are some considerations when deciding on what MA you should use in a given situation

Answer 12

• rope and equip available
• size of load
• number of haulers available
• haul field or work area
• the “throw” same as haul field?
• adaptability

Question 13

What are some considerations concerning a Ganged On MA

Answer 13

• will need a haul slacker
• will need two ropes or a split rope
• Can prebuild
• easier knot pass
• more versatile anchors

Question 14

What are some considerations concerning an integral MA

Answer 14

• only one rope needed
• does not need a haul slacker
• more complicated and gear intensive knot pass
• can not prebuild

Question 15

What equipment is needed to build a 3:1 Integral MA (not including the anchor, rigplate, or the carabiner used to attach end of the rope to the shelf

Answer 15

• One rope
• two pulleys (single or double)
• three prusiks (One set of blue and red, and a red)
• two carabiners

Question 16

What equipment is needed to build a 3:1 Cod Integral MA (not including the anchor, rigplate, or the carabiner used to attach end of the rope to the shelf

Answer 16

• One rope
• three pulleys (or two if a double is used to incorporate the Cod
• three prusiks
• three carabiners (or two if a double pulley is used)

Question 17

What equipment is needed to build a 4:1 Ganged On (not including the anchor, rigplate, or the carabiner used to attach end of the rope to the shelf

Answer 17

• Two ropes (or one rope split in two)
• two double pulleys
• three prusiks
• four carabiners

Question 18

What equipment is needed to build a 4:1 Pig MA (not including the anchor, rigplate, or the carabiner used to attach end of the rope to the shelf

Answer 18

• Two ropes (or one rope split into three)
• Two pulleys (single or double)
• Four Prusiks
• Five Carabiners

Question 19

What equipment is needed to build a 5:1 Integral MA (not including the anchor, rigplate, or the carabiner used to attach end of the rope to the shelf

Answer 19

• One rope
• Two double Pulleys
• Three prusiks
• two carabiners

Question 20

What equipment is needed to build a 5:1 Ganged ON MA (not including the anchor, rigplate, or the carabiner used to attach end of the rope to the shelf

Answer 20

• Two Ropes (or one rope split into two)
• Two double pulleys
• Three Prusiks
• Four Carabiners

Question 21

What equipment is needed to build a 6:1 (“C” on a “Z”) MA (not including the anchor, rigplate, or the carabiner used to attach end of the rope to the shelf

Answer 21

• Two ropes (or one rope split into two)
• Three Pulleys (singles or doubles)
• Four prusiks
• Four carabiners