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ACCIDENTS AND FINDINGS

FIONA (31 August 1988)

The forward cargo tank of the FIONA exploded while a surveyor measured cargo temperature prior to unloading, resulting in one death. The National Transportation Safety Board (NTSB) concluded that

• A steam leak in the tank caused static charge to be generated
• The charge accumulated on an ungrounded temperature probe and discharged as the probe was withdrawn from the tank,
• The resulting sparks ignited explosive vapors from the residue of the tank's previous cargo [9].

NTSB's recommendations addressed the foregoing items and other contributory factors:

• FIONA's cargo tanks should have been inerted.
• Inert gas system (IGS) should be used with all cargoes unless tanks are gas free.
• The main source of the explosive vapors was contamination of the cargo by previous condensate cargo, while release of light hydrocarbons by the fuel oil in the tank may have been contributory.
• Masters of vessels carrying Grade E cargoes should certify that explosive vapors are not present prior to sampling or measuring cargoes with a combustible gas indicator device.
• The static charge was generated by a steam leak in the cargo heating pipes and accumulated on an ungrounded temperature probe. Better maintenance might have prevented the casualty. · The probe lacked a precautionary nameplate stating the, need for grounding the instrument during use. Underwriters Laboratory UL) should adopt the Canadian Standards Association requirement for such a nameplate. The internal grounding wiring on these probes should also be checked periodically.

AMERICAN EAGLE (26, 27 February 1984)

The AMERICAN EAGLE, sailing in ballast, exploded and sank in the Gulf of Mexico with the loss of four lives. The NTSB concluded that the most probable cause of the explosion was the use of a steam powered air ventilator fitted with a long plastic sleeve in a non-gas free tank

The ship had been carrying fuel oil and gasoline. The tank in question had been washed, but not gas freed; an explosive mixture in the tank was possible.

The probable cause of ignition was an incentive spark between the tank structure and charged steam condensate falling from the plastic sleeve through which the air was being driven.

The crew was unaware of the clear warning against the introduction of steam into potentially explosive atmospheres. The use of non-conductive material contributed to the accumulation of static charge.

As a result of the accident, NTSB recommended that "A Manual for the Safe Handling of Flammable and Combustible Liquids and Other Hazardous Products", be revised to thoroughly address static electricity hazards on tank vessels.

 

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Hypothermia

Key points

• Hypothermia is defined as a core body temperature below 35ºC (95ºF)
• Suspect toxic, metabolic, or endocrine etiology in patients who present with hypothermia without a history of environmental exposure
• Initial management includes rewarming, cardiopulmonary and hemodynamic stabilization, trauma assessment, finger stick for blood glucose determination, blood tests to assess patient's general biochemical and physiologic status, and an electrocardiogram (ECG) and cardiac monitoring to identify arrhythmias
• Rewarm at rates of 0.5ºC to 2ºC per hour (0.9ºF-3.6ºF/h) using one or more rewarming techniques, including passive external rewarming with removal of wet clothing and wrapping in warm blankets; active external rewarming with hot water bottles and other devices; active core rewarming via airway and heated body cavity irrigation; and extracorporeal blood rewarming via cardiopulmonary bypass
• Patients with severe hypothermia (<30°C or 86°F) are at risk of ventricular arrhythmias and require more rapid rewarming with active internal rewarming techniques
• Monitor patient during active core warming for dysrhythmias or vascular collapse
• Cardiac drugs and defibrillation are generally less effective or ineffective in the presence of acidosis, hypoxia, and hypothermia
• Patient movement should be kept to a minimum as it can lead to dysrhythmias
• Patients with severe hypothermia may appear to be dead, but should be rewarmed before terminating resuscitative efforts. Due to vasoconstriction and profound bradycardia that can be seen in severe hypothermia, palpating pulses can be difficult
• Hypothermia induces a neuroprotective state, and there are many case reports of patients surviving prolonged resuscitation attempts

Background

Description

• Hypothermia is defined as a core body temperature below 35ºC (95ºF)
  • Mild: 35ºC to 32ºC (95ºF-90ºF)
  • Moderate: 32ºC to 30ºC (90ºF-86ºF)
  • Severe: below 30ºC (<86ºF)
• Classification by temperature is not universal and actual temperature cut-offs vary by source
• The body has a limited capacity to increase heat production, and hypothermia occurs when heat loss is greater than heat production
• Hypothermia can be considered:
  • Primary due to straightforward exposure to cold environments
  • Secondary due to disease or an environmental exposure coupled with another reason, such as intoxication
  • Intentional as in cardiac bypass or post-resuscitation therapeutic hypothermia
• Hypothermia affects all organs of the body; minor deviations from normal temperature can lead to clinically significant dysfunction
• Absence of respiratory and cardiac function may return as patients are rewarmed

Epidemiology

• Varies widely depending on location and season
• Estimates are difficult to quantify as hypothermia is often listed as a secondary diagnosis
• 0.3/100,000 deaths from primary hypothermia
• Extremes of age (young children and the elderly) are the most vulnerable to hypothermic injury
• Adults have highest probability of being exposed to hypothermic conditions
• Males more affected than females
• In urban populations of the U.S., most cases of hypothermia are due to homelessness, mental illness, or illicit drug and/or alcohol use
• Outdoor workers are at increased risk
• Poverty may be associated with inadequate indoor heating and poor clothing and predispose to climate-related hypothermia

Causes and risk factors

Causes:

• Decreased heat production:
  • Nutritional depletion: malnutrition, hypoglycemia, extremes of age (the very young and the very old)
  • Endocrine disorders: hypopituitarism, hypoadrenalism, hypothyroidism
  • Neuromuscular dysfunction: impaired shivering, immobility
• Increased heat loss:
  • Environmental exposure: trauma, mental illness, disorientation, suicide, myocardial infarction, recreational exposure such as skiing or mountain climbing
  • Drug intoxication: alcohol, toxins, sedative/hypnotics, narcotics, barbiturates
  • Skin disorders: burns
  • Iatrogenic: prolonged cardiopulmonary resuscitation (CPR), postsurgical, therapeutic, cold intravenous fluids, overcooling of patients with heat stroke
• Impaired thermoregulation:
  • Central: spinal cord injury, cerebrovascular accident
  • Peripheral: neuropathy, diabetes
  • Metabolic/toxic: drugs (benzodiazepines, phenothiazines, tricyclic antidepressants, barbiturates, lithium, clonidine), anorexia, diabetic ketoacidosis, hepatic failure, uremia, lactic acidosis, hypoglycemia
• Miscellaneous:
  • Sepsis: Gram-negative sepsis, meningitis
  • Pancreatitis
  • Uremia
  • Vascular insufficiency
  • Carcinomatosis
  • Seizure disorder
  • Peritonitis

Risk factors:

• Age: Mild hypothermia is more common in the elderly because of comorbidities, medications, reduced metabolic rate, and immobility. Elderly patients may have poor nutrition or be challenged by poverty resulting in inadequate heating
• Arterial disease
• Diabetes mellitus (type 1 or type 2)
• Altered mental status
• Homelessness
• Drug use (licit and illicit)

Screening

Summary approach

Not applicable.

Primary prevention

Summary approach

• Limit exposure to cold environmental temperature
  • If hypothermia is due to inadequate housing, clothing, or heat source, refer patient to social services
  • Extremes of age and those patients with medical, nutritional, or another propensity for hypothermia should be extra vigilant in minimizing cold exposure
• Avoid alcohol and illicit drugs during periods of cold exposure. Abstinence from alcohol and illicit drugs will minimize cases of hypothermia
• Satisfy fluid and nutritional requirements; correct dietary deficiencies

CHALLENGES BEFORE MARINE PROFESSION IN INDIA - A SMALL THOUGHT

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Indian officers are specially a respected lot in the maritime industry, even though the crew lag behind the Filipinos who are natural born seamen due to the natural conditions prevailing there with thousands of island around; still Indian crew have also started to work their ways to the top. Academically Indians have done a good job especially when we compare their analytical skills and coming to a logical conclusion faster and effectively solving the problem successfully. Hats off to the senior marine officers who have imparted their knowledge and skills to the new seafarers. However there are areas where we have to improve and also move forward to keep up our standards. Some common points that are affecting the Indian seafarers are due to the large flooding of colleges approved by DG which have not only become commercial but also has brought down the standard of the officers. Of late DG has also started to crack down on these institutes and that is a good sign. More and more practical skills need to be imparted to officers from both the deck and engine as just being good theoretically doesn’t mean that you are perfect and can handle all situations. When one is faced with a tough situation it is also his practical knowledge that comes to play and help save time and money, as shipping is all about money these days. This is where the importance of the new maritime institutes and the faculty who train the candidates are put to test. Psychometric tests adopted during selection procedures of the seafarers have already started yielding results with people with strong will power and cool and composed mind coming up the stream; they have also helped the sea farers to undergo tension and breakdowns in a cool and composed manner. The faculty should also emphasize on a holistic approach of teaching when they do with the seafarers. Even though the opportunities for seafarers in the shore job has increased with the presence of a lot of institutes popping up the same cannot be said about the standard these institutes are are bringing out in the form of cadets; there has definitely been a downfall in the professional standards of the candidates passing out of some of these institutes; hence the challenge before the maritime industry  in India is multifold with students only concerned about their promotion and salaries and not interested in their jobs.Most of the candidates who join are also only influenced by the lifestyle of the seafarers but haven’t really got down to see what the profession is really about; also we cannot blame them completely as institutes in order to get more students also have lowered their standards of selection and criteria as it has really become a good money making business.

WHAT IS NEEDED

A)    A reality check on all institutes and cancel licences to those underperforming and cannot offer a placement

B)    Compulsory psychometric tests for selecting candidates apart from their academic performance

C)    Candidates to be exposed to the reality of the job and should be well briefed about the requirements of the job

D)    Institutes to have more practical based training to help the candidate in their job onboard, ship in campus is a right step towards this goal,but adequate training is also required and must be provided by the institutes.

E)     Experienced trainers required in the institutes who can impart both practical and theoretical knowledge

F)     Corrupt practices in maritime industry specially for employment and agencies who just take candidates by taking money must be stopped immediately.

G)    Competition among seafarers for best seafarer in each company should be encouraged based on performance

H)    Candidates who clear their exams in a limited time also to be rewarded suitably by the companies

I)       Promotions also to be both experienced and knowledge based.

For all this to happen the faculty who train the seafarers will be the ones responsible to bring out the best in the candidates and also impart the best knowledge and training required ; so its just not enough that the trainers undergo a TOTA course or are doing a side business more dedication and teamwork from them is also required. Also there should be workshops held for the entire teaching faculty from across India regularly to impart them with the new technical knowledge and skills in teaching the new generation sea farers. Knowledge is definitely to be shared but should not be made into a business and a money making racket.

Even though it’s a small initiative I have tried to put the cause of Indian seafarers specially the new generation ones problems and the immediate requirements that has to be addressed to make India a no.1 maritime nation in the world, I welcome your kind suggestions and other ideas to make our nation a maritime force in the world.

                                                                                                                          

 

IMO symbols

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RT -FLEX ENGINES

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The Wärtsilä RT-flex50 low-speed two-stroke marine diesel engine:
 common-rail system for fuel injection.
 common rail system for exhaust valve actuation, and
 full electronic control of these engine functions
   instead of the traditional mechanical camshaft system.

Benefits:

Smokeless operation at all operating speeds

Lower steady running speeds, in the range of 10–15 per cent nominal speed, obtained smokelessly through sequential shut-off of injectors while continuing to run on all cylinders.

Reduced running costs through reduced part-load fuel consumption and longer times between overhauls
Simpler setting of the engine. The ‘as-new’ running settings are automatically maintained.

Reduced maintenance costs through precise volumetric fuel injection control leading to extendable times between overhauls.

The common-rail system with its volumetric control gives excellent balance in engine power developed between cylinders and between cycles, with precise injection timing and equalised thermal loads
Reliability is given by long-term testing of common-rail hardware in component test rigs.

Higher availability owing to the integrated monitoring functions.

High availability also given by the built-in redundancy, provided by the ample capacity and duplication in the supply pumps, main delivery pipes, crank-angle sensors, electronic control units and other key elements.
The common rail for fuel injection is a single-piece pipe running the length of the engine at just below the cylinder cover level.

 The common rail and other related pipe work are arranged beneath the top engine platform and readily accessible from above.

The common rail is fed with heated fuel oil at the usual high pressure (nominally 1000 bar) ready for injection.
The supply unit for the fuel has a number of high-pressure pumps actuated by cams driven through gearing from the crankshaft.

Fuel is delivered from this common rail through a
separate injection control unit (ICU), mounted directly on the rail, for each engine cylinder to the standard fuel injection valves which are operated in the usual way by the high-pressure fuel oil.

Using quick-acting Wärtsilä rail valves, they regulate the timing of fuel injection, control the
volume of fuel injected, and set the shape of the injection pattern.

Each ICU serves the two fuel injection valves in its corresponding cylinder cover.
Each injection valve is separately controlled so that, although they normally act in unison, they can also be programmed to operate
separately as necessary.

The exhaust valves are operated in the same way as in RTA engines by a hydraulic pushrod but actuating energy now comes from a servo oil rail at 200 bar pressure.

The servo oil is supplied by high-pressure hydraulic pumps incorporated in the supply unit with the fuel supply pumps. The electronically-controlled actuating unit for each cylinder gives full flexibility for setting the timing of valve opening and closing.

All functions in the RT-flex system are controlled and monitored through the integrated Wärtsilä WECS-9520 electronic control system.

This is a modular system with a separate FCM-20 microprocessor control unit for each cylinder.

An additional FCM-20 unit provides all connections to other systems such as the remote control and alarm systems.

Lower turbocharger efficiencies at part load normally result in low excess combustion air with fixed valve timing.
Another important contribution to fuel economy of the RT-flex50 engines is the capability to adapt easily the injection timing to various fuel properties having a poor combustion behaviour.
Exhaust gas emissions have become an important aspect of marine diesel engines. All Wärtsilä RTA and RT-flex engines as standard comply with the NOX emissions limit set by IMO in Annex VI of the MARPOL 73/78 convention.
   RT-flex engines, however, come comfortably below this NOX limit by virtue of their extremely wide flexibility in optimising the fuel injection and exhaust
   valve processes.
 
A visible benefit of RT-flex engines is their smokeless operation at all ship speeds.
The superior combustion with the common-rail system is largely because the fuel injection pressure is maintained at the optimum level irrespective of engine speed.
At very low speeds, individual fuel injectors are selectively shut off and the exhaust valve timing adapted to help to keep smoke emissions below the visible limit.


 

VIT AND SUPER VIT A DISCUSSION

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Modern large slow speed MAN B&W 2-stroke engines have Super VIT mechanism fitted to advance fuel injection at lower loads for increasing maximum firing pressure resulting better fuel economy. Details of Super VIT are available in the engine manuals.

Why use the term "Super"? was there an "ordinary" VIT earlier, which has been changed to Super VIT?
If yes, can I have a brief description of how the ordinary (non-Super) VIT worked?

Before the Super VIT was introduced variable injection timing was obtained by means of a special profile on the fuel pump plunger. Hence there was a fixed relationship between the injection timing and the fuel index. Thus it was not possible to adjust the fuel index of the individual pumps without also altering the injection timing. For this reason the Super VIT was introduced, where it is possible to adjust the fuel index and the injection timing independently.

Is it possible to achieve Super VIT action by means of mechanical linkage or can it be only done if we have electronic (microprocessor) controlled fuel injection system. Or is it right to say that most efficient Super VIT can only be achieved by electronic fuel injection?

The Super VIT is available in both a mechanical and an electronic version. In the electronic version an I/P converter supplies the pilot air pressure to the individual servo cylinders, instead of the pilot valve activated by the fuel rack used in the mechanical version. The I/P converter receives its pilot signal from the governor system.

The advantage of the electronic version is that the break-point is calculated from the actual conditions, why the ambient conditions are taken into account. The engine load is calculated from the engine speed and the fuel index, while the compression pressure is calculated from the scavenging air pressure. Based on these calculations the governor calculates the output to the I/P converter

Am I right in assuming break point is where max cylinder pressure has been reached before MCR which is about 85% MCR when using VIT, after which injection timing is retarded back to its original setting at 100% MCR

Also, does the MAN B&W engine have a fuel quality setting lever on the VIT control similar to that used on the Sulzer RTA, or must the fuel pumps be adjusted individually if a fuel of differing ignition quality is bunkered.

The breakpoint is the point where the maximum cylinder pressure has been reached and the injection timing is advanced the most. Above the breakpoint the injection timing is gradually retarded back until it reaches its original setting at 100% MCR load. The position of the breakpoint is determined by the layout of the engine. Formerly it was generally considered to be at approximately 85% MCR load, but it also has to be ensured that the maximum pressure rise from compression to maximum cylinder pressure is 35 bar or less (recommended by MAN B&W Diesel A/S). For this reason the breakpoint has tended to be somewhat higher on the latest engines (approximately 90% MCR load).

In order to compensate for fuel related differences in the maximum cylinder pressure it is possible to adjust the VIT according to the experience with the different fuels.
In case of the mechanical VIT an offset is introduced by moving the pilot valve bracket horizontally towards or away from the lever, by means of the adjusting screws.
In case of the electronic VIT it is possible to adjust an offset value on the governor panel.

What the term fuel index and how is it adjusted?

The fuel index is an indication of the active stroke of the fuel pump. This is controlled by push rods on the individual fuel pumps connected to the fuel rack, which in turn is controlled by the engine governor.

When the engine is given a speed command the governor increases the fuel index, subject to certain limitations, untill the requested engine speed is reached

if i am not wrong, the vit pilot line pressure increases to approx 3 kg at break point and then reduces till the mcr keeping the pmax const.
i would like to draw your attention to the inlet pressure of this vit pilot valve which is 7 kg (control line pr).
i had experienced sticking of this pilot valve and full 7 kg outlet pressure was fed to the servo positioners. luckily it was noticed immediately and corrective actions were taken.
suppose this had happened during ums period in an engine room, would any enine alarm sound?
what would the peak pressure be during that limited time with pilot line pressure at 7 kg and an engine operating at 90 % mcr?

If the servo signal increases way beyond the normal operating range, e.g. as you state the worst case is equal to the control system pressure of 7 bar, this will naturally result in an increased pressure rise from the compression pressure to the maximum pressure.
No alarm is provided for this malfunction, as it does not directly influence the operation of the engine. The increased pressure rise will actually improve the performance of the engine, but will over time overstress the piston rings. If such a condition is allowed to exist for a long time, cylinder condition problems are thus likely to occur. However, an abnormal servo signal ought to be discovered by the engine crew during their routine inspection rounds - even with the engine room under UMS conditions.

But if we observe the VIT index at break point, this would be around 6 notch and the peak pressure developed at this point would be the design 140 bar in the cylinder. If 7 bar is admitted to the servo the VIT index becomes around 14 notch. and as each notch gives an increase in peak pressure of 1 bar, the peak pressure may exceed by 8 bars. this difference may increase more if the engine is operated above the break point. Wouldn’t this effect the load on the bearings and other running gear if the engine is operated in this condition for more than 8 hrs.
My doubt is , why isn’t a reducer fitted before the vit pilot valve, when the max pressure needed is 3.5 bars, which is given during engine starting and astern movements.
the data above are speculated and may not be fully correct, please correct if wrong.

The actual VIT index at the break point depends on a variety of factors, e.g. fuel properties and ambient conditions. The latter is taken into account in the calculations of the electronic VIT version, as the scavenging pressure is used in the calculations. Consequently, it is not possible to state default values for the VIT index break point setting or rate of change.

In any case, the mechanical limits of the VIT system also have to be considered. The travel of the servo actuators is designed to be going from a minimum at a servo signal of 0.5 bar to a maximum at a servo signal of 5.0 bar, why the mechanical limit is reached earlier than a servo signal of 7 bar would otherwise indicate. In case of the mechanical VIT system, the break point is determined by the point where the lever rests on both pivot points. In this case it is not possible to depress the pressure adjusting valve further, thus preventing a too high servo signal as the control air inlet will always press the piston of the pressure adjusting valve against the lever.

Even if the maximum pressure is over the specified maximum, the engine is not overloaded due to this. The engine load is determined by the power required to turn the propeller at the requested revolutions and a malfunction of the VIT system does not change this and e.g. the auxiliary systems are not affected by this either. Consequently, the only real impact on the engine is the increased pressure differential over the piston rings, due to the too high pressure rise from the compression pressure to the maximum pressure, and a very limited increase to the bearing load.

As stated earlier, the over stressing of the piston rings may possibly require maintenance, if the malfunction is allowed to persist, but does not affect the possibility to safely manoeuvre the engine. Hence, it has not been deemed necessary to introduce an alarm or other measures to prevent or limit the duration of such a malfunction.

 

ENERGY AUDIT

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What is an Energy Audit ? An energy audit is a preliminary activity towards instituting energy efficiency programs in an establishment. It consists of activities that seek to identify conservation opportunities preliminary to the development of an energy savings program. The Role of an Energy Audit To institute the correct energy efficiency programs, you have to know first which areas in your establishment unnecessarily consume too much energy, e.g. which is the most cost-effective to improve. An energy audit identifies where energy is being consumed and assesses energy saving opportunities - so you get to save money where it counts the most. In the factory, doing an energy audit increases awareness of energy issues among plant personnel, making them more knowledgeable about proper practices that will make them more productive. An energy audit in effect gauges the energy efficiency of your plant against “best practices”. When used as a “baseline” for tracking yearly progress against targets, an energy audit becomes the best first step towards saving money in the production plant. Contents of an Audit An energy audit seeks to document things that are sometimes ignored in the plant, such as the energy being used on site per year, which processes use the energy, and the opportunities for savings. In so doing, it assesses the effectiveness of management structure for controlling energy use and implementing changes. The energy audit report establishes the needs for plant metering and monitoring, enabling the plant manager to institutionalize the practice and hence, save money for the years to come. The energy audit action plan lists the steps and sets the preliminary budget for the energy management program. 1. Analysis of energy use Identifying where energy is used is useful because it identifies which areas the audit should focus on and raises awareness of energy use and cost. The results of the analysis can be used in the review of management structures and procedures for controlling energy use. Analysis of energy use can be done by installing submeters in different plant locations to pinpoint actual energy usage per area. This is a good source data for allocating energy use. The plant manager can also list all equipment used and the corresponding operating hours. With this information, he can create spreadsheet information and generate charts useful for analysis. Important Points to Consider When Collecting Site Load Data a.     Operating hours - This can be gathered from plant personnel. It is important to ensure the accuracy of this data because much of the potential for energy savings lies on correct estimation of the equipment’s operating hours. b.     Duty cycle - Machines such as large electric motors have varying loads and hence, different power requirements. c.     Actual power consumed - For electric power users, this is based on either 3-phase current/voltage readings or power analyzer measurements (e.g., direct kW which incorporates power factor). For fuel users, tank readings of monthly consumption estimates and flow meters with totalization can be sources of measurement. 2. Identification of energy projects Opportunities for energy savings can range from the simplest, such as lighting retrofits, to the most complex such as the installation of a cogeneration plant. The important thing to remember is to focus on major energy users and areas. Always apply the 80/20 rule, focus on opportunities that provide 80% of the saving but require 20% input. After the preliminary identification of opportunities, spend more time on those which have shorter payback periods. 3. Cost benefit analysis The identified energy conservation opportunities should be analyzed in terms of the costs of implementing the project versus the benefits that can be gained. If you want to, say, install a heat plate exchanger to recover waste heat, you need to calculate the total cost of installation and compare that with the savings you will derive from recovering waste heat. It makes sense to go on with the project if there is a net positive benefit from the project. 4. Action plan to set implementation priority After passing the cost benefit test, an action plan should be developed to ensure that the opportunities identified are implemented. The action plan should include all the major steps for implementing the opportunity as well as the people responsible. Furthermore, there should be a plan for monitoring the results.