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Difficulty: HardResolve the Paradox

A commercial maritime shipping company applied specialized hydrodynamic micro-grooved coatings to the hulls of its transoceanic container vessels. In controlled basin trials, these coatings consistently lowered skin-friction drag by 8 percent, producing a 7 to 9 percent reduction in fuel consumption per nautical mile at standard cruising speeds. However, during the two years following the fleet-wide application under standard operating schedules, the company's total marine fuel consumption increased substantially, even though the fleet's total number of voyages, average cargo weight per ship, and navigational routes remained identical to those of the preceding two years.

Which of the following, if true, most helps to resolve the apparent discrepancy described above?

  1. A
    The micro-grooved surface coating also inhibited the adherence of barnacles and algae, which typically build up on submerged hulls over long voyages and increase water resistance.
  2. B
    The initial cost of manufacturing and applying the specialized hull coatings across the entire container fleet exceeded the projected economic savings from reduced fuel usage over the two-year period.
  3. Because the drag-reducing coating allowed the vessels to travel significantly faster without straining their engines, operators routinely maintained higher speeds to shorten transit times, operating in a speed regime where total fuel consumption per nautical mile is much higher.Answer
  4. D
    Competing shipping lines operating on the same ocean routes without the specialized coating reported steady fuel consumption rates throughout the same two-year timeframe.
  5. E
    Open-ocean swell conditions cause micro-grooved coatings to lose all hydrodynamic drag-reducing properties within the first few hundred nautical miles of a transoceanic voyage.

Answer

The statement explaining that vessel operators used the reduced drag to travel at much higher cruising speeds—where overall fuel burn per mile escalates—most effectively resolves the discrepancy.
The correct response introduces a behavioral adjustment made possible by the innovation: because the coating reduced drag, operators increased cruising speeds to shorten voyage durations. Because vessel fuel consumption scales sharply with higher speeds, the decision to travel faster resulted in a net increase in total fuel consumed per voyage, perfectly harmonizing the coating's drag-reducing properties with the higher overall fuel consumption.

Step-by-Step Solution

1
Identify the two competing, paradoxical facts in the stimulus.
Fact 1: The hull coating reduces friction drag and lowers fuel consumption per nautical mile by 7 to 9 percent at standard cruising speeds. Fact 2: In real-world service with identical voyage counts, cargo weights, and routes, total fuel consumption rose substantially.
Resolving a paradox requires a clear understanding of the exact tension between the established premises.
2
Determine the necessary bridging relationship required to resolve the paradox without contradicting either premise.
An external or behavioral factor must have changed during real-world operations that caused total fuel expenditure to escalate despite the per-mile hydrodynamic efficiency at standard speeds.
The correct answer must allow both the drag-reduction capability and the increased fuel usage to be true simultaneously.
3
Evaluate the answer choices to identify the causal mechanism that reconciles both facts.
The choice noting that operators utilized the coating to travel at substantially faster speeds accounts for the increased fuel consumption, because hydrodynamic drag increases exponentially with speed, outpacing the efficiency gains of the coating.
This compensatory behavioral change explains why overall fuel usage increased under identical routes and cargo loads.

Key Concept

Resolving an apparent discrepancy through compensatory behavioral changes (the rebound effect) in operational systems.
Estimated Time:1m 45s
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Topics

Resolve the Paradox

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