The method
Before using the result
- Fuel volume and consumption use a consistent basis. Constant consumption/speed only; reserve is supplied by the user and is not an operational recommendation.
Worked examples
These original training examples illustrate the method for USCG Captain's License (OUPV/Master). Use the matching “Load example” button above to explore a variation; example values are not equipment settings or prescribed criteria.
1. Worked example
Deduct an independently selected reserve before estimating endurance. Compare a constant-rate range estimate with the reasons real voyage consumption can differ.
- Fuel aboard
- 1,000 L
- Fuel held in reserve
- 200 L
- Constant consumption
- 0.036 m³/h
- Constant speed
- 10 kn
- Usable fuel = 1 − 0.2 = 0.8 m³.
- Endurance = 0.8 / 0.00001 = 80000 s.
- Range = 80000 × 5.144444444444445 m.
- Usable fuel: 0.8 m³
- Endurance: 80,000 s
- Constant-speed range: 411,555.6 m
2. Comparison example
Compare a different supplied condition using the same method. For Marine Exam, the important check is that the input meaning, units and method assumptions still match the problem.
- Fuel aboard
- 1,000 L
- Fuel held in reserve
- 300 L
- Constant consumption
- 0.036 m³/h
- Constant speed
- 10 kn
- Usable fuel = 1 − 0.3 = 0.7 m³.
- Endurance = 0.7 / 0.00001 = 69999.99999999999 s.
- Range = 69999.99999999999 × 5.144444444444445 m.
- Usable fuel: 0.7 m³
- Endurance: 70,000 s
- Constant-speed range: 360,111.1 m
Check your understanding
1. Which relationship is used?
Usable fuel = aboard − reserve; endurance = usable/consumption; range = endurance × speed.
2. Which assumption should you check first?
Fuel volume and consumption use a consistent basis. Constant consumption/speed only; reserve is supplied by the user and is not an operational recommendation.
3. How should you verify a different unit system?
Convert every input to the displayed calculation units first. Equivalent physical inputs must give equivalent results; a unit label alone does not convert a number.
Continue with the matching exam topic
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