Bunkering Procedure – Ship Refuelling

The bunkering procedure on a vessel has historically been associated with numerous incidents and accidents. These operations involve the transfer of volatile substances, including various types of fuel oil and gas. Bunkering of fuel or diesel oil necessitates meticulous attention and vigilance to mitigate the risks of fire hazards and oil spills. You should always choose a specialist company with decades of experience, such as MH Bland, to provide bunkering services. This article aims to document the bunkering process aboard ships and highlight critical considerations that must be addressed during bunkering operations.

What Does “bunker” Mean?

In the shipping industry, “bunker” refers to fuel and lubrication oils stored on a ship for machinery use, but they are not called bunker when transported to another port for discharge. Instead, they are only called bunker when transferred from a vessel or container to a ship. The process is then called “bunkering”.

Types of Bunker (or Fuel)

There are many types of fuel used by global shipping. This is a summary of those:

• Heavy fuel oil (HFO) – High emissions and requires pre-heating
• Intermediate fuel oil (IFO) – As with HFO but has lower sulphur content
• Low sulphur fuel oil (LSFO) – Typically less than 0.5% sulphur
• Ultra-low sulphur fuel oil (ULSFO) – Less than 0.1% sulphur & doesn’t require pre-heating
• Marine gas oil (MGO) – No preheating and very low emissions
• Marine diesel oil (MDO) – No preheating and low emissions
• Liquefied natural gas (LNG) – Cryogenic so requires heating before use, very low emissions

How Bunker is Transferred to Ships

Bunker fuel can be delivered to a vessel through various methods, with the specific mode of transfer depending on the grade or type of fuel being supplied. Multiple types of facilities exist to provide certain grades of marine fuel or lubricating oil to ships. Typically a small barge or vessel carrying bunker fuel can be employed to transfer marine fuel oil, such as heavy fuel oil, to the ship. For smaller quantities, such as lubricating oil, marine gas oil, or liquefied natural gas, the fuel can be supplied via trucks. For a complete rundown on how bunker can be transferred please see three methods for transferring fuel to ships.

The Bunkering Procedure in Detail

a) Pre-Bunkering

1. The chief engineer defines the bunkering plan, primarily the grades and quantities of fuel needed for a voyage. This may involve a single refuelling at port of origin or involve a stop in a tax neutral bunkering territory, such as Gibraltar
2. His bunkering plan should be guided by the international standard ISO Regulation 8217
3. Fuel and grades already on board should be measured by tank soundings
4. Existing onboard fuel should be moved to tanks and isolated if incoming fuel types are incompatible
5. A meeting takes place involving all personnel involved in the process. This will define fuel grades, tanks to be filled, quantities, order of filling and awareness of the SOPEP (Ship Oil Pollution Emergency Plan)
6. All crew members involved are issued with a checklist specific to their role
7. Approval of the plan by the ships master

Once the plan is approved then the fuel is ordered from a specialist bunkering provider, such as MH Bland

b) Bunkering

1. Pre-bunkering meeting to confirm that each member knows his roles and responsibilities
2. Plug all deck scuppers (drainage holes, usually leading to the sea) and save-all trays (these are essentially drip trays to catch oil or fuel leaks)
3. Ensure overflow tank is empty if too much bunker is taken into the tanks
4. Adequate light and sounding (for communications and emergencies)
5. No smoking signs to be placed and obeyed
6. Raise a red flag or light not he masthead to indicate refuelling 
7. Communication of the bunker plan to the fuel barge person in charge
8. Paperwork checked prior to pumping
9. Pump rates and amounts agreed between ship and fuel barge
10. Fuel barge connects the hose / pipe to the ship 
11. Final checks and agreements are made between the 2 crews
12. The manifold valve is opened to commence refuelling

c) Whilst Bunkering

1. When pumping starts the flow rate is kept low, giving time to react to emergencies such as open valves or incorrect destination tanks
2. Once onboard crew determines there are no issues the pump rate is increased to that specified by the bunkering plan
3. Filling continues until the agreed amount has been transferred to that particular tank
4. The tank is usually filled to a maximum of 90%, with the fuel barge slowing pump rate as this maximum is approached
5. Tank gauges show the amount of bunker in the tank but soundings are usually taken as well – in case of gauge failure or incorrect readings
6. Temperature of the bunker is continuously monitored as this affects the volume of liquid being supplied. Fuel samples are also taken for analysis later
7. If fuel is required in other tanks then the crew will change the valves as required, being careful to not mix fuel grades or overfill tanks
8. Bunker quantity is monitored continuously and the ship being refilled may request top ups to the agreed amounts

d) Post Bunkering

1. Following refuelling and agreement between crews that the correct amounts and grades have been delivered, the pipes will be cleared with compressed air to clear them of fuel
2. All necessary valves will be closed prior to the above
3. If there is a disagreement about amount of bunker delivered then a note of protest is issued indicating these differences of opinion. It can later be used to settle between the shipping company and the bunker provider
4. The samples collected during bunkering will be sent to a lab for analysis. The receiving ship is not to use the new fuel supplies until the lab clears the samples as matching what the supplier claims to have provided
5. Finally, the changes made prior to bunkering are undone. Eg: the scuppers are opened to allow drainage to the ocean etc.

Summary

Bunkering, the process of transferring fuel to maritime vessels, is a high-risk operation that demands rigorous safety protocols and adherence to regulatory standards. The fuel supplied varies from heavy fuel oil to cleaner alternatives such as marine gas oil and liquefied natural gas.

The procedure is divided into four distinct stages: pre-bunkering, which involves planning and safety inspections; bunkering, where fuel is transferred under controlled conditions following established protocols; during bunkering, characterised by continuous monitoring of flow rates, tank levels, and fuel quality; and post-bunkering, involving system checks, sample testing, and final verification procedures.

Performed by skilled providers, bunkering aims to ensure the safe and efficient refuelling of vessels while reducing potential environmental hazards.