With a typical voyage racking up hundreds or even thousands of nautical miles, whether it be collecting cargoes from ports or transporting cruise passengers between exotic locations, one of the key aspects of controlling fuel costs is ensuring you’re getting what you pay for – both in terms of quality and quantity.
When it comes to fuelling or ‘bunkering’ of a vessel, shipping owners must be able to ensure that the amount and type of fuel delivered is the same as that agreed with the parties supplying the fuel. With bunkering contracts often negotiated many miles from the point of actual fuelling, it can sometimes be difficult for shipowners to be certain that what is being delivered is exactly what they’ve paid for.
While measuring the fuel flow as it is pumping on board is a good start, problems can still arise if the right technology is not used. Mismeasurement of fuel quantities can arise from a phenomenon known as the ‘cappuccino effect’, where air blown through the fuel hose – either accidentally, or deliberately – can cause frothing, similar to that seen on the surface of a cup of cappuccino. When this occurs, it can lead to fuel level reading errors that make it seem that the tanks are full when they aren’t.
As well as resulting in companies paying for fuel they haven’t received, this phenomenon also increases the risk that the vessel will not have enough fuel for its journey, requiring it to make an unscheduled stop at another port. In such situations, the consequences can include both delays and extra costs, not only for extra fuel but also potentially in the form of lost profits through late delivery or a lost delivery or loading slot.
Using the wrong style of flowmeters can exacerbate this situation. A flowmeter measuring just volume, for example, would see the froth as part of the measurement, resulting in the actual level of fuel being miscalculated.