- A vessel has bunkered 250 tonnes of diesel fuel of which 10% is assumed to be unpumpable. The average combined sea load of the vessel is 2800kW with a stated specific consumption of 0.35kg/kWh at a speed of 18 knots.
Calculate EACH of the following:
(a) the daily fuel consumption of the vessel;(4)
(b) the safe steaming range of the vessel.(6)
(a) the daily fuel consumption of the vessel;(4)
Here’s how to calculate the daily fuel consumption of the vessel:
1. Calculate Usable Fuel:
- Unpumpable fuel: 250 tonnes * 10% = 25 tonnes
- Usable fuel: 250 tonnes – 25 tonnes = 225 tonnes
2. Calculate Daily Fuel Consumption in kg:
- Average power consumption: 2800 kW
- Specific fuel consumption: 0.35 kg/kWh
- Hours in a day: 24
- Daily consumption (kg): 2800 kW * 0.35 kg/kWh * 24 hours = 23520 kg
3. Convert to Tonnes:
- 1 tonne = 1000 kg
- Daily consumption (tonnes): 23520 kg / 1000 kg/tonne = 23.52 tonnes
Answer: The daily fuel consumption of the vessel is 23.52 tonnes.
(b) the safe steaming range of the vessel.(6)
To determine the safe steaming range, we need to consider the usable fuel and the daily fuel consumption:
- Usable fuel: 225 tonnes
- Daily consumption: 23.52 tonnes
Safe steaming range (in days) = Usable fuel / Daily consumption = 225 tonnes / 23.52 tonnes/day ≈ 9.56 days
Therefore, the safe steaming range of the vessel is approximately 9.56 days.
It’s important to note that this is a theoretical maximum. In practice, it’s advisable to maintain a safety margin and not consume all the fuel. Factors like weather conditions, unexpected delays, and the need to maintain a reserve for emergencies should be taken into account when planning voyages.