Propuesta práctica de Aprendizaje Cooperativo (AC)

(5) To lift the load two feet with this system, you must pull four feet of rope through the pulley.

(6) When each rope is equalized, divide by two. So if the load weighs 100 lbs., each line has 50 lbs. of supported weight.

c. Construction of the 3:1 ratio system (Z-Pulley) (1) For tightening a rope installation:

(a) Anchor one end of the rope to a suitable far anchor using the tree wrap method.

(b) Tie a swami wrap around the near anchor and clip a steel-locking carabiner with the gate up and large axis facing the far anchor. This carabiner is referred to as the Main Anchor Carabiner (MAC).

(c) Take the running end of the rope from the far anchor and clip it into the MAC. Tie a stopper knot (Auto block), with a short prusik on the rope and attach it back into the MAC and lock it down.

AUTO BLOCK

(d) Using another short prusik, come out from the swami wrap a few feet and tie a stopper knot (French prusik) on the rope and clip a steel locking carabiner into it

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with the direction of pull towards the near anchor. Clip the running end of the rope from the Auto block into the carabiner and lock it down.

(e) Now pull the running end of the rope to tighten the rope installation.

TIGHTENING A 3:1 MECH ADVANTAGE

d. Construction of the 9:1 ratio system (Z-Z Pulley) (1) For tightening a rope installation:

(a) Anchor one end of the rope to a suitable far anchor using the tree wrap method.

(b) Tie a swami wrap around the near anchor and clip a steel locking carabiner through all the wraps with the gate up and large axis facing the far anchor. This carabiner is referred to as the Main Anchor Carabiner (MAC).

(c) Take the running end of the rope from the far anchor and clip it into the MAC. Tie a stopper knot (Auto block), with a short prusik, on the rope and attach it back into the MAC and lock it down.

(d) Using another short prusik, come out from the swami wrap a few feet and tie a stopper knot (French prusik) on the rope and clip a steel locking carabiner into it with the direction of pull towards the near anchor. Clip the running end of the rope from the Auto block into the carabiner and lock it down.

(e) Take the running end of the rope back to the swami wrap; attach another steel locking carabiner into the MAC with the large axis facing down and out to the far anchor. Clip the rope into this carabiner and lock it down.

CARABINER INTO THE MAC

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(f) Holding the rope that runs between the 2^nd stopper knot and the carabiner hanging from the MAC, go back to a few inches before the French prusik and tie a 3^rd stopper knot (French prusik) on that line of rope with a steel locking carabiner attached to it. Take the running end of the rope and clip it into the carabiner and lock it down.

CLIPPING INTO THE PRUSIKS

(g) Now pull the running end of the rope to tighten the rope installation.

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TIGHTENING A 9:1 MECH ADVANTAGE

NOTE: Care must be taken when increasing the ratio system. Breakage and damage of the ropes, carabiners and pulleys is very possible if the force end of the rope is greater than the load end of the rope. No more than two men will tension the installation at any time if using pulleys.

TRANSITION: Are there any questions over the construction of the systems? Because we are Marines, we are used to carrying a great deal of weight. But when we are in the mountains we should take every opportunity to lighten our loads and reduce the amount of work we need to do.

If you have no questions for me, then I have some for you.

PRACTICE (CONC)

a. Students will use a mechanical advantage system to tighten a rope installation. Practical application of this will be on the one Rope Bridge.

PROVIDE HELP (CONC)

a. The instructors will assist the students when constructing the one Rope Bridge.

OPPORTUNITY FOR QUESTIONS (3 Min)

1.

QUESTIONS FROM THE CLASS 2.

QUESTIONS TO THE CLASS

Q. What are the two practical uses for the mechanical advantage system?

A. (1) As a tightening system.

(2) As a device to raise personnel or equipment up steep or vertical terrain.

SUMMARY (2 Min)

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a. During this period of instruction we have discussed the terms and definitions, the practical uses, the equipment required for the construction of the 2:1 (C-Pulley), the 3:1 (Z-Pulley) and the 9:1 (Z-Z Pulley) ratio systems.

b. Those of you with IRF's please fill them out at this time and turn them in to the instructor.

We will now take a short break.

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UNITED STATES MARINE CORPS

1. GAIN ATTENTION. At times in mountainous terrain, it will become necessary to cross-rivers or streams. If the obstacle is a river, it can normally be crossed by utilizing various fording techniques. If it is a ravine, you may have to rappel down one side and scramble up the other. The most expeditious technique that can be used for crossing such an obstacle, particularly where a large body of men are involved, is by the use of a man portable easily erected and dismantled rope bridge.

2. OVERVIEW. The purpose of this period of instruction is to provide the students with the necessary skills required to cross-streams using a one-rope bridge. This material will be covered by discussing site selection, how to estimate the distance to be crossed, construction, crossing techniques, rescue techniques, and retrieving the bridge. This lesson relates to mountain movement.

INSTRUCTOR NOTE: Have students read learning objectives.

3. INTRODUCE LEARNING OBJECTIVES

1. TERMINAL LEARNING OBJECTIVES. In a summer mountainous environment, conduct bridging, in accordance with the references.

2. ENABLING LEARNING OBJECTIVES (SML) and (ACC)

1 )Without the aid of references, list in writing the criteria for site selection for a one-rope bridge, in accordance with the reference(s).

2 )Without the aid of references, given a MAC Kit, and a simulated or actual obstacle, construct a one rope bridge, in a specified time limit and in accordance with the references.

3 )In a summer mountainous environment, cross a one-rope bridge using the rappel seat

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