Tricks of the Bunker Trade: The Cappuccino Effect

by Kaivan H. Chinoy, Petro Inspect / The Bunker Detectives
Thursday July 25, 2013

The "Cappuccino Effect" (also sometimes known as the "Coca Cola Effect") essentially may be described by a frothing/bubbling effect caused by compressed air blown through the delivery hose.

The aerated bunkers when sounded will give the impression that the fuel is delivered as ordered.

In fact after some time when the entrapped air in suspension settles out of the fuel oil the oil level drops and a short fall is discovered.

In large bunker deliveries this could be considerable with huge financial implications.

We have often been asked why the flow meter cannot detect the air being introduced in the system and compensate accordingly.

Well, most flow meters in use today are of either the wrong type or the wrong size. In other words are not technologically advanced.

All the standard flow meters will only measure the volume of throughput and not the actual mass of fuel being delivered. As a result when air is introduced into the system, which is essentially 'small air bubbles' - the flow meter will register it as volume.

However, there are flow meters out in the market which are capable of measuring the true quantity (mass) of the fuel delivered.

One such meter is the 'Coriolis Mass Meter' - it has been in existence for quite some time now and is only getting better.

Coriolis meters take direct mass flow measurements using the Coriolis Effect (a deflection of moving objects when they are viewed in a rotating reference frame – we won't be discussing this effect as this is beyond the scope of this article).

Coriolis meters are less sensitive to pressure, temperature, viscosity, and density changes, allowing them to measure liquids, slurries and gases accurately without the need for compensation.

These meters having no moving parts require little maintenance however, the initial cost and line modifications is usually a deterrent for many ship operators for not installing it.

Key Notes:

  • Cappuccino Effect can be eliminated by sounding the fuel tanks prior to blowing through.
  • Look out for any signs of foam on the surface of the fuel or excessive bubbles on the sounding tape.
  • Look out for any unusual noises from the bunker barge or excessive vibration of the bunker delivery hose (especially if you know that the tanks on the bunker barge will not be empty and thus stripping of the tanks could be safely ruled out)
  • Remember whenever in doubt or have concerns always issue a letter of protest

About Petro Inspect and The Bunker Detectives

Bunker Detectives

Petro Inspect, previous known only as The Bunker Detectives, are a dedicated team who primarily help ship charterers' & bunker brokers deal with bunker quantity disputes (which do not fall under P&I cover for charterers'), and also offer an exclusive service to ship charterers' dealing with 'Bad' Bunker dispute claims, such as the supply of contaminated or off- specification bunkers.

The core services provided under the banner of 'Bunker Detective' are 221B Surveys (aka Bunker Detective Surveys), Bunker Stem Surveys (aka Bunker Quantity Surveys - BQS) and Charter On/Off Hire and Condition Surveys, as well as a bunker fuel concealment detection services.

About Kaivan H. Chinoy

A qualified Mercantile Marine Officer with an MSc Degree in "Technical Management of Ship Operations," prior to founding AVA Marine Kaivan spent over 15 years involved in extensive marine operations including vessel navigation, cargo handling, accident investigations, project cargo risk management, and marine cargo surveying.

To contact the editor responsible for this story email us at editor@shipandbunker.com