TB 9-2350-292-10

RECOVERY PROCEDURES (CON’T.)

(CON’T.)

RECO

STEP 4. OBTAIN RESISTANCE

Compute the tackle resistance and total resistance.

Determine the resistance of the tackle. The percent of

the load resistance, as determined in STEP 2, is multi-

plied by the number of sheaves in the rigging. The

determined resistance of the tackle added to the load

resistance equals the total resistance.

Total effort available is winch capacity multiplied by the

mechanical advantage, as computed in STEP 3. If effort

available is more than total resistance, proceed to STEP

5.

If it is less, go to STEP 3 and add mechanical

advantage.

STEP 5. VERIFY SOLUTION

Compute line forces to compare with the winch and dead

line capacities. Divide the total resistance (STEP 4) by

the mechanical advantage (STEP 3). The result is the

force of the fall line. The fall line force must be less than

the capacity of effort. Therefore, this step of the recovery

procedure is the key step to solving the problem.

When verifying the solution, if the computed fall line

force is greater than the effort, the mechanical advan-

tage must be increased. Note that no physical work has

occurred up to this point. As a result,

no time is lost moving equipment or

having to re-erect rigging equip-

ment. Compute the dead line

force, determine the required

strength of equipment capacity

and choose the correct equip-

ment to use as dead lines.

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