Your vessel arrives in port with sufficient fuel to steam 595 miles at 14 knots. If you are unable to take on bunkers, at what speed must you proceed to reach your next port, 707 miles distant?
• Fuel endurance is proportional to (speed × time) only if fuel consumption per hour stays the same, but large changes in speed usually change consumption per mile. • Distance, speed, time relationship: ( \text{Speed} = \frac{\text{Distance}}{\text{Time}} \). • On many exam problems like this, you assume fuel consumption per hour is proportional to the cube of the speed unless told otherwise. Verify if that assumption is needed here.
• First, find how many hours you can steam at 14 knots with the fuel you have, using the 595-mile figure. • Next, relate your fuel endurance at 14 knots to what it would be at the new speed, keeping total fuel constant. • Set up an equation so that the fuel used to go 707 miles at the unknown speed equals the fuel you know you have (based on the 595 miles at 14 knots), then solve for speed.
• Be clear what is assumed constant: fuel per hour, fuel per mile, or a power–speed relationship (like speed cubed). • Check that your final speed, when used over 707 miles, does not exceed the fuel endurance implied by 595 miles at 14 knots. • After solving, confirm your speed is one of the multiple-choice options and is reasonable (slower than 14 knots, since you need to stretch your fuel farther).
No comments yet
Be the first to share your thoughts!