🔍 Key Concepts

• Relationship between speed and fuel consumption for displacement vessels (fuel use changes roughly with the cube of speed) • How to set up a proportion or ratio comparing two operating conditions (known fuel at one speed vs. unknown fuel at another) • Careful unit consistency – both speeds in knots, fuel in barrels per day

💭 Think About

• How does fuel consumption typically change when you reduce speed on a displacement hull – does it go up, down, or stay the same? By a little or a lot? • If fuel use is roughly proportional to the cube of speed, how can you compare fuel at 18 knots to fuel at 14 knots using a ratio? • Once you compute the new fuel consumption, which multiple‑choice option is closest to your calculated value?

✅ Before You Answer

• Be sure you apply the same exponent to both speeds when using the speed–fuel relationship (e.g., both speeds cubed if using a cube law). • Double‑check your ratio setup: put the known condition on one side and the unknown condition on the other in a consistent way. • Confirm that your final answer is less than 215 bbl/day (since the speed is lower) and that it matches one of the four options.