Fuels and Lubricants

Avoiding common pitfalls in fuel and lubrication matters


Malcolm Latarche
Malcolm Latarche
ShipInsight

27 June 2019

Avoiding common pitfalls in fuel and lubrication matters

Since the first motor ship went into service in 1912, ships have mostly used MDO and MGO as fuel with IFO and HFO appearing later and, being cheaper, rapidly becoming more favoured for larger ship types. LNG as a marine fuel – other than for steam turbine powered LNG carriers – has less than two decades of being used.

With shipping being obliged to seek cleaner alternative fuels for the future, there will inevitably be a steep learning curve for crewmembers who will likely be required to deal with many different fuel types within their careers.

Since there will always be occasions when a seafarer’s encounter with a different fuel will be their first, it seems sensible for training and safety management systems to ensure an understanding of risks, hazards and special measures that need to be taken with each fuel type is in place. This will need to cover all aspects of different fuel types used on board a ship including the fuel treatment system, fire-fighting or other safety matters and the method of bunkering.

Most of the small-scale pollution events in shipping occur as a consequence of mistakes during bunkering so this is an issue that needs addressing but as well as anti-pollution measures and safety, crew must also be aware of all aspects of bunkering relating to quality and quantity delivered. Surprisingly in the past this has not been fully addressed in STCW so there has been no requirement for crew to undergo any formal training in bunkering.

Although there is no formal requirement, there are training courses available to attend and also training films on the subject. In addition, organisations such as class societies and P&I clubs frequently disseminate advice on the matter. In April 2016, the International Bunker Industry Association (IBIA) joined with UK-based South Shields Marine School at South Tyneside College, to develop a course unit on bunkering essentials for merchant navy cadets and engineering officers taking their Class One and Class Two certificates of competency.

The course aims to explain the fundamentals of the bunker industry, the key regulations affecting shipping today, along with the latest industry challenges and developments.

Perhaps because of its unique characteristics, LNG bunkering has received some attention from the IMO and under the IGF Code which came into effect in January 2017, some new requirements have been incorporated into STCW. Handling LNG fuel and other low flashpoint fuels on ships along with rules for specific equipment training and operations on LNG-fuelled ships including bunkering operations and some aspects of LNG-terminal operations are now mandatory for officers and crew serving on gas-fuelled ships. To advance their careers, seafarers must have at least one month of approved seagoing service to include a minimum three bunkering operations of which two could be replaced by simulator training of bunkering operations.

The importance of samples

During delivery of bunkers samples should be taken for analysis in case of dispute and also for compliance with IMO rules. The samples should be properly labelled and stored safely on board. Because of some highly publicised cases of contaminated bunkers causing damage to engines, some operators have adopted the habit of having all fuel analysed before use.

There are many independent laboratories who offer such services and some of the leading classification societies also have their own fuel testing programmes. If taking advantage of such a service, the method sampling will be determined by the service provider. There are a growing number of kits that allow the crew to make some types of checks on board as well and these can overcome the need to wait days or weeks before learning if the fuel is suitable for use. It is also good practice to segregate the new fuel and where possible not use it until the result of the sample analysis is available.

This last point looks to become more important from now onward as ships begin using the new 2020-compliant fuels. As well as proving the sulphur level meets the new requirement, stability will need to be checked in some way although as yet there is no quick method of doing this.

It is to be hoped that most bunker suppliers are honest but there are far too many cases of fraudulent means of short-delivering and delivering off-spec and contaminated fuels recorded each year to demonstrate that not all are. The contamination cases are sometimes accidental but there are many documented cases of bunker fuel being used as a medium for disposing of hazardous waste chemicals.

Sadly it is also true that some seafarers are also dishonest and willing accomplices in defrauding shipowners by taking bribes to sign false delivery notes. If the vessel is on time charter when such crimes are committed, the owner may not be financially out of pocket by virtue of the short delivery but may find himself on the end of a legal dispute over consumption and performance claims from the charterer.

The advent of Monitoring, Reporting and Verification (MRV) by the IMO and the EU as a means of initially measuring CO2 emissions but potentially as a charging basis for a future market-based measure on shipping is another reason why accurate records of quantities delivered is gaining added importance beyond the commercial considerations alone.

Getting what’s been paid for

One of the main causes of short deliveries is a failure to recognise or understand the relationship between temperature, volume and mass. Unlike fuelling motor vehicles ashore where volume is the pricing factor, bunkers for ships are almost ordered by mass (tonnage).

However, measuring the ordered quantity on delivery is done by volume taking into account the temperature of the fuel. Fuel expands as temperature increases so for the same mass of fuel the volume will be more at a higher fuel temperature than at a lower fuel temperature.

Bunker delivery notes (BDNs) usually detail both mass and volume but whenever there is any doubt as to the actual quantity delivered, the engineer officer signing for the fuel should always endorse it as being for ‘volume only’ adding a clause along the lines of “actual weight to be determined after testing of representative samples”.

Any question as to the temperature of the fuel also needs to be remarked upon as this will be crucial to determining actual mass. The temperature is often measured on the barge which may make checking difficult but whenever possible the temperature should be seen by a crew member or temperatures of the ships’ bunker tanks taken at intervals immediately before, during and immediately after the bunkering operation.

One usually-deliberate means of bunker suppliers making short deliveries is to pump air into the bunker flow during delivery. This causes the fuel to froth, fooling some types of flow meters into measuring a higher amount of fuel. The frothiness of the fuel has given this practice the nickname of the ‘cappuccino effect’. Not only does the effect give false flow meter readings, it can also mean that measurements taken by sounding the bunker tanks are inaccurate, at least until all the air dissipates. The shortage in delivered quantities can be significant ranging from 2% to 5% or more.

There are several ways in which air may be introduced into fuel oil:

  • The bunker barge may inject compressed air into its tanks prior to joint soundings being taken to increase the apparent volume of the fuel oil before it is transferred.
  • Compressed air may be injected into the fuel oil during the transfer, either in the vicinity of the discharge pump, or into the tank or into the discharge line. This may be by using the compressed air equipment designed to blow through the pipelines after discharge, or via a separate system.
  • The stripping of bunker tanks using a positive displacement pump means that air will be drawn into the fuel oil when pumped. Consequently, excessive stripping by the bunker barge may also result in the cappuccino effect.
  • Preventing a short delivery through the cappuccino effect requires vigilance by the crew during bunkering but there are several signs and sounds that are giveaways that something is amiss. These include:
    • Suspect connections on the bunker barge’s supply pump and pipework – these can be quite small as only compressed air is being injected.
  • Check the manifold sampling point at regular intervals for frothing or excessive air bubbles.
  • Look for foam and/or frothing on the surface of the fuel oil on the barge prior to bunkering and on the vessel while bunkering is taking place and on completion.
  • Check for bubbles on sounding tapes.
  • Unusual noises at the manifold, supply line or fuel tank vent head.
  • Unusual movement of the supply hose during bunkering.
  • Fuel density – if too low for its temperature, that may indicate presence of excess air.

The temperature of the fuel oil should be measured before the transfer takes place so that the fuel oil density can be calculated accurately.

If it is suspected that air may have been introduced into the fuel oil, an engineer should board the bunker barge and ask to see the line blowing arrangements and the air compressor. If these have recently been in use, the compressor and its connections will be warm, while the compressed air delivery line will be cold. Empty compressed air bottles may also provide an indication that the fuel oil has been injected with air.

The cappuccino effect cannot be detected by most types of flow meter but mass flow meters (MFMs) using a device known as a Coriolis meter are much more accurate as they do measure mass rather than volume. Very few ships have been fitted with MFMs but they are available from several suppliers. Although they are more accurate, MFMs are not infallible and can be cheated.

Dilution of fuel

Under the ISO 8217 standards, the water content of most residual fuels is limited to 0.5% v/v and in most cases is usually considerably below this level. However, fuel can sometimes contain higher levels as a result of an accident such as a leaking heating coil or as a consequence of fraudulent and deliberate injection of water. If samples indicate a high level of water beyond that allowed by the ISO 8217 standard, then a letter of protest should be issued.

The ship’s fuel treatment system should be able to remove water but if this is not the case then the fuel may have to be landed ashore. Fuel samples provided by the barge may not have any traces of water as the samples may have been taken prior to bunkering and mixing of water. Fuel samples should always be collected during bunkering and not before or after. Samples should only be signed for those actually witnessed. Use of water-finding paste on the sounding tape works with distillate but not with residual fuels.

More grades, more problems

The advent of ECAs not only means that a shipowner without a scrubber is obliged to burn more expensive fuels but also those fuels need to be segregated. Therefore, it is necessary to have different storage, settling and service tanks for each grade of fuel. This can be provided for in newbuildings easily enough but for existing vessels the choice may come down to running all the time on more expensive fuels or having existing tanks divided during a drydocking to allow for the extra number of tanks needed.

Even where ships have a number of bunker tanks available, using two or more different grades of fuel may make management extremely difficult. This is particularly true when the size of individual tanks means that only relatively large volumes can be allocated to any particular fuel type.

After 2020, when only ships equipped with scrubbers will be able to burn cheaper HFO, older ships which do not plan to fit scrubbers will need to clean and prepare tanks for compliant fuel. If operating mainly in the tropics, such ships can probably remove any tank heating equipment but for ships that sail regularly in other latitudes, it may be a wise precaution to retain the heaters to avoid waxing of MDO.

Blended fuels

As demand for low sulphur fuels has increased, the availability of inherently low-sulphur crude oil stock has not kept pace. As a consequence, much of the low-sulphur fuel on the market is a result of blending fuels with different sulphur contents to make one with the appropriate level of sulphur. Often the viscosities and other characteristics of the fuels blended are very different and this can lead to problems further down the line.

It is not unknown for blended fuels to separate out in a ship’s tanks or to become unstable when mixed with other fuel during subsequent bunkering operations. If a blended fuel separates it is possible that the ship will at some point be burning fuel that exceeds the sulphur limit permitted by MARPOL. This could lead to a ship being detained or penalised by an unsympathetic port state.

Connected with this issue is the interpretation of MARPOL regulations where limits on sulphur are set to a single decimal point and the question of whether rounding down is permitted where a fuel may have a sulphur content very slightly above that shown in MARPOL.

Blended fuels may also have very poor ignition characteristics causing fouling of cylinders, turbochargers and exhaust systems and in worst case scenarios engine failure and power blackout. Such problems are most likely to occur during switch over between standard and low-sulphur fuels which usually takes place as vessels are entering areas of heavy traffic and thus increasing the risk of collision or worse.

As fuel suppliers develop new products to meet the 2020 reduction to 0.5% sulphur levels outside of ECAs, the problems associated with compatibility are likely to grow. Ships fitted with scrubbers may suffer less as the standard HFO fuels are less likely to be affected but if the availability of HFO is affected by lower sales levels resulting in lower stocking, then such ships may find that they are obliged to accept other fuel grades from time to time and that these may not mix easily if at all with standard HFO.

In addition, a small number of ports and states have banned the use of open loop scrubbers. This ban is already in operation in Norway’s Heritage Fiords and one ship has been penalised for contravening it. Thus, ships which could comply with the 2020 sulphur cap by using scrubbers must also ensure a supply of compliant fuel on board for use when operating in waters affected by the ban. The bans have been introduced because the wash water from open-loop scrubbers is considered by some to be a pollutant.

Switch over to meet sulphur rules

As of May 2019 there are four emission control areas (ECAs) established under MARPOL and a handful of regional regimes – notably all of the EU and parts of China – where there are regulations on sulphur levels allowed in marine fuels. To meet the requirements, any ship without a scrubber is obliged to switch fuels unless it is already running on ultra-low sulphur fuel.

There are two issues relating to a switch to a lower sulphur fuel. The first is related to the treatment of the fuel itself and the second affects only two-stroke, low-speed engines and involves matching the upper cylinder lubricant to the different fuels involved.

Many ships not subject to mandatory low-sulphur fuel limits already switch from HFO to marine diesel oil (MDO) during port operations, so the procedure is not entirely alien, but in ECAs there is a burden of proof upon the ship to show that at the point of entry into the controlled zone it was burning only the permitted fuels.

That involves a gradual changeover and if the switch is from ordinary HFO to low-sulphur HFO there will be a need for the temperature of the low-sulphur product to be managed so that a smooth switch can be achieved. Even so, the time taken to achieve compliance will depend upon the amount of fuel contained in the system and the tank space available for service fuel.

Because heavy residual fuels will be used at temperatures above the flashpoint of low-sulphur distillates, when the switch involves these types of product, the temperature in the fuel lines must be monitored and managed with great care. This is especially true if the engine makers require the residual fuel to have a particular viscosity which may involve cooling it below ambient temperature. Class societies and industry organisations have offered a lot of advice on this subject, even going to the extent of preparing comprehensive manuals and guidelines for operators.

The need to switch lube oils is to ensure a match between the base number of the lube and the sulphur level of the fuel and is discussed further in the chapter on engine lubricants.

There are alternatives to managing the switch between fuels manually with at least four automatic systems available. For a manual change, the largest designer of two-stroke engines MAN Energy Solutions recommends crew to reduce engine loads to 25-40% before changing fuel type while the automatic switching systems enable a controlled and safe changeover independent of engine load. They do this through continuously checking temperature versus time and use software to operate coolers to adjust the MGO temperature.

As with some of the other devices, full details of the switch between fuels including time and location (taken from the ship’s GPS) is recorded and can even be transmitted ashore using the ship’s communication system.

Choices and charterers

As possibly the highest of all operating costs, fuel and lube purchases need to be subject to proper oversight. When a ship is operated for the owner’s own account, control of choice of fuel and its suitability is clearly a matter for the owner but when time chartered out, fuel supply is taken over by the time charterer. Lubricants almost always stay within the control of the owner or ship manager.

Regardless of the time charterer’s status, the operator should always ensure that full details of acceptable fuel grades are included in the charter party. While the time charterer will normally consult with the ship’s officers on quantities of fuel needed for particular voyages, the choice of supplier and actual grade ordered is out of the ship’s control and it often happens that the time charterer orders the cheapest fuel available even though it may not be in accordance with the quality criteria in the charter party. If that happens, the master should seek advice from his owner, but the concerns of the technical staff are sometimes ignored by management especially in times when employment for vessels is hard to find.

It is vital that any problems with supplied fuel are brought to the charterer’s attention because in the event that a problem occurs that causes an off-hire situation there will be no recourse for the owner if the charterer can plead ignorance of the consequences of using inadequate fuel.

Another problem that is frequently encountered when vessels are time chartered is when the time charterer hits financial difficulties and does not pay all outstanding costs incurred. Far too many owners have been caught in this situation and the legal consequences are that they become responsible for most if not all of the unpaid debts. There are clauses that can be inserted in charter parties that seek to minimise the risk but these are not always helpful or enforceable. One clause which provides a good example of the practices that owners should adopt is the BIMCO Bunker Non-Lien Clause for Time Charter Parties.

BIMCO has also developed two clauses for use in charter parties that cover potential problems associated with the 2020 rule changes.