Vehicle Recovery Techniques Flashcards

Which type of rigging configuration doubles the pulling force of a winch while halving the line speed?

Answer: Double-line pull using a snatch block

Threading the winch cable through a snatch block anchored to a fixed point and back to the vehicle creates a double-line pull that doubles mechanical advantage while reducing retrieval speed by half.

When recovering a vehicle from a flooded roadway, the MOST important initial step is:

Answer: Verify the water depth and flow rate to determine if recovery is safe

Assessing water depth and current flow determines whether the recovery itself is safe for personnel and equipment, since moving water can destabilize the recovery vehicle and personnel.

A recovery operator is extracting a vehicle buried up to its axles in sand. Traction boards (recovery boards) are placed:

Answer: Under and in front of the drive wheels to create a surface to grip

Traction boards placed under and in front of drive wheels give the vehicle a firm surface to grip as it accelerates forward, helping it drive itself out of the soft ground.

What does the term 'block and tackle' refer to in the context of WreckMaster recovery operations?

Answer: A system of pulleys and ropes that multiplies pulling force

Block and tackle systems use multiple snatch blocks and cable runs to multiply the applied pulling force through mechanical advantage, enabling recovery of very heavy vehicles with limited winch capacity.

When a vehicle has gone over an embankment and is resting against a tree, the safest initial recovery approach is to:

Answer: Assess the tree's stability and the vehicle's contact points before rigging

Assessing whether the tree is load-bearing, whether the vehicle is structurally compromised, and what forces are at play prevents the vehicle from rolling further during rigging.

The maximum safe working load (SWL) of a recovery strap is typically rated at what fraction of its minimum breaking strength (MBS)?

Answer: One-half of the MBS (2:1 safety factor)

Recovery straps and chains are typically rated at 50% of their minimum breaking strength (a 2:1 safety factor) to account for shock loads, wear, and environmental degradation.

During a multi-vehicle pileup recovery, WreckMaster protocol requires that recovery of vehicles proceed in which order?

Answer: Top-most or outermost vehicles first, working inward

Recovering the top-most and outermost vehicles first prevents cascading collapse or movement of vehicles beneath or behind them, protecting personnel and preserving remaining vehicle integrity.