In 2012 Singapore became the centre of a bunkering dispute which resulted in a full investigation into what is known in the marine industry as the ‘cappuccino effect’.
What is the cappuccino effect?
Cappuccino bunkers are caused by compressed air being blown into the fuel oil during the transfer process. The blown air increases the apparent volume of fuel oil, but once the process is completed air rises to the surface resulting in froth and foam sitting on the surface of the fuel in a cappuccino effect.
As a result of this malpractice the shortfall for vessels can be significant, the vessel in Singapore ended up with 46 tonnes less fuel.
How is it caused?
The cappuccino effect occurs when air is injected into fuel oil, which can be done in a couple of different ways during transfer
- Compressed air can be blown into tanks before it’s transferred to increase the apparent volume of the fuel oil.
- Air can be injected into the fuel oil during transfer via the discharge pump or into the discharge line. Compressed air equipment, usually used to blow through pipelines after discharge, may be used in this process or a separate system can be used.
What are the signs?
Whilst the resulting ‘cappuccino effect’ is one of the most visual alerts to this problem, there are other tell-tale signs that something isn’t right throughout the transfer process.
- Foam or frothing on the surface of the fuel oil prior to bunkering and on a vessel whilst transfer is taking place. Also look for bubbles and frothing on sounding tape or brass bob throughout the transfer process.
- Check the pipework for suspect connections before the transfer begins. Look out for suspect connections on the supply pump and pipework where air injection lines can be used to blow air into fuel oil. Make time to inspect the line blowing arrangements before transfer begins.
- Unusual noises heard by the crew of the vessel in Singapore were the first indication that something was wrong. If compressed air has been injected you’ll hear gurgling noises coming from the supply line or at the manifold. The fuel tank vent head and ball or float valves may also vibrate or rattle if there is an excessive amount of air present. You may also notice the supply hose moving around in a jolting or shuddering motion.
Bunker fuel sampling ensures a representative sample is captured for testing and analysis, it forms the basis of all discussion, debate or dispute resolution relating to bunkering. The Parker Kittiwake bunker fuel samplers are lightweight and easy to install and come complete with bunker fuel sampler joint rings.
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Tel: +44 1903 731470