Ships in their operations often suffer damage; the damage could be due to weather, wear and tear or due to accidents. In every such condition it is imperative that the ship’s worthiness to face all the situations is maintained. Such maintenance requires assessment of damage, recording of the same and repairing of the same.
Process of assessment & recording damage What is damage?
Let us consider a very common case from our daily lives. A normal healthy man goes about his daily routine shouldering his responsibilities and obligations well. This man catches some infection and is unable to work as he does not feel well and has high temperature. The infection is diagnosed to be from mosquito bites, takes medication and rest for a few days and is healthy and well again. He feels strong as before and is working as efficient as before the infection. Had he not taken proper medication following analysis of his symptoms, some body organs could have got damaged permanently or he could have died in the worst case.
The status of any machine or a system (system can be defined as a stand alone machine or a combination of machines which perform linked to each other to deliver a common or single product service) can be put into any of the following categories
Inactive: System is shut down but can be energised.
Normal: Operating as designed.
Alarm: Needs attention to maintain its normal status.
Damaged: Unable to operate as designed due to breakdown.
An alarm can be defined as the ‘means of bringing to attention, visually, audibly or both, any condition that needs or may need attention to restore the normal operational conditions of a system’.
The scope and purpose of an alarm is to attract attention to conditions different from the normal status. If the status is not restored back to normal, further series of actions might result in shut down or permanent damage or destruction of a particular system. Now with this in mind relate back to our opening example and you will see a direct relationship.
Every damage incidence results in some loss, i.e.
- Loss of productivity,
- Loss of time,
- loss of property,
- Loss of life etc.
Of all these losses the loss of human life is the biggest loss (even on this over populated planet!). This must always be the first priority and it must be prevented at all costs.
A vessel can get damaged from several causes but all damages on ships are always interrelated. The damage may be due to an interaction between two ships, between a ship and a terminal or even between a ship and the environment. Within the scope of the present module, let us look at the following four:
- Damage from Contact.
- Damage from Fire.
- Weather damages.
- Damage to the Environment.
We shall now look more closely at the above and see how to assess, record and make good the damages and mitigate the loss so that the ship can complete the voyage.
Damage from contact
A vessel, usually weighing thousands of tons, is a moving mass with a large kinetic energy. Even when moving at very slow speeds the kinetic energy that a vessel possesses is very high.
Just to remind you the kinetic energy of a moving object is the product of its mass and the square of its velocity. Perhaps it would not be out of place to state that action is equal to reaction.
When this moving mass hits anything, it not only damages the object that it hits, but the object also damages the ship and these can be severe. If the contact is between two ships moving at their full speeds the kinetic energy is so high that the result is a disaster. So let us say one cause of damage is the ship coming into contact / collision with another.
Incidentally contact between two or more floating objects (two ships, ship & buoy etc.) is called ‘collision’ while a vessel touching a fixed object is usually referred to as ‘contact’.
In any collision or contact, the immediate danger is flooding, i.e. ingress of water into the ship. Water ingress, if sufficiently large, can cause a ship to capsize or sink in a very short time. Water ingress into any ship is a multi-pronged attack on the safety of the ship. For now we will consider only two aspects.
Water enters the ship from a ruptured area, which was intact before the rupture and therefore provided buoyancy for the vessel. After the rupture the vessel looses the buoyancy to the same extent as the volume of the compartment ruptured.
Seawater weighs approximate 1025kg / m3. More the water ingress into the ship, more the weight added on board. This extra weight therefore causes the ship to sink further into the sea, again a reduction in the safety factor.
The water ingress would depend upon rate of ingress. This in turn depends on the location of rupture, physical size (area) of the rupture and the depth of the rupture below the sea surface.
Larger the area larger the ingress, deeper the rupture higher the rate of ingress. Hence large quantities would enter the ship in relatively shorter time if the damage were well below the water line. The amount of water ingress can be calculated but it is of little importance at the time of the accident. However we need to know the location of the damage and it’s extent, to take corrective measures.
‘Minor’ contact damage is where a rupture has not taken place and no water ingress has occurred. The vessel therefore is not in danger of sinking. In any case the impact has caused the vessels structure to absorb the energy and would cause some deformation or dents. This will have to be brought back to its original strength.
The help at hand
Informatively today’s ships are pretty complicated to deal with when major damages takes place. The Classification Societies have now introduced a ” Help” programme. This programme envisages that when a ship registered with them is in difficulty, they investigate the ship stability and ability to sustain the damage. Such classification societies are on the alert at all times and render advice all rounds the clock.
Damage from fire:
Statistics show that maximum loss to property and loss of lives is attributable to explosions and fires on board ships than any other cause. Explosion is just an extension of an uncontrolled fire and hence for our purpose explosion also means fire, with much more destructive potential at that!
Fire is a chemical reaction that takes place when certain conditions are created, what we call the completion of the ‘FIRE TRIANGLE. This has already been discussed at length. Fire can burn and destroy just about anything and everything that is found on board.
In shipboard fire fighting:
- The escape area is rather limited
- The means of fighting the fire are also limited,
On board fires can therefore take devastating proportions, as outside help is non-existent.
In the technological modern era, weather remains as unpredictable as it was to the farmers in the old days. Prediction methods for weather at sea have come a long way. It is however far from being absolutely accurate as the global weather patterns are still under study. Storms, unpredictable heavy seas and swell, therefore, can be rather harsh and unkind to a sailor at sea. It is also not possible to construct a ship that can stand the severest of the weather conditions within economical constraints. Prudent sailors therefore avoid areas of storm fury.
If a vessel does encounter bad weather, the possible damage that she may suffer is also impossible to predict. However an alert master knows that:
- Weathertight integrity of the ship may suffer and the water could enter cargo holds,
- Cargo within the holds could get loose and break free,
- Cargo on deck could break its lashing and get lost overboard or
The structure of the vessel may suffer damage.
The assessment of any damage depends principally on some questions that we must ask. They are:
- What part of the ship is damaged?
- What is the extent of the damage? (Length and breadth or depth of the dent, number of plates affected, the impact of the damage on the watertightness or weathertightness)
- Does it affect the seaworthiness?
- Has it caused any injury or loss of life? \
- Is there any pollution?
Damage to the environment:
The environment issues, so far having occupied the back seat, have now come to the forefront in the last few years, after environment has taken a beating for decades. Everyone today, whether ashore or at sea, is talking about ‘pollution prevention. Pollution, incidentally, is defined as release of substances, accidentally or otherwise, that can be harmful to the environment. Most sailors commonly relate pollution with sea only but the air pollution by the ships too has been an issue of concern lately.
Damage to environment could be placed broadly under two categories, pollution of seas & pollution of air. Entry of oil & its products including plastics, into the sea is a major source of environmental damage. Oil in the seawater will interfere with the ecological and marine life and upset the balance, which can take number of years to correct itself.
Reporting and recording damages:
Why report and record?
Accidents and resulting damage lead to unsafe conditions. From our first day at sea we have been talking about safety. This safety has to be maintained by following correct procedures. Such procedures can be corrected only if it is recorded and investigated
All incidents resulting into damages are investigated by the ships officers first and the several different authorities and bodies later. The level of investigation and scrutiny by such bodies shall depend upon the severity of the damage. Properly maintained records help the investigating team to recreate the circumstances and analyse the root cause of damage. Maintaining proper records is therefore of paramount importance.
The aims while recording events should be to only record the facts and events and not the views and causes as perceived by the recorder. The incidences must be recorded in chronological order as they had occurred giving as many details as possible. Such records should include
- The time of occurrence,
- State of weather,
- Which other ship / individuals were involved,
- Nature of damage suffered and action taken before, during and after the incident,
- Photographs, as far as possible.
It is only then that the investigating team will be able to recreate the situation and get to the root cause.
You have seen operations on your ship, such as loading / discharging of cargo, going alongside or working with bunkering barges alongside. All these operations can be a cause for ship damage. Look around your ship, you will find some bent rails on the ship’s side, especially in the proximity of the gangways, derricks & cranes. You will also find some broken rails in the engine room in the vicinity of engine room crane. A little closer look and one can observe dents on the ship’s side as it came alongside too fast or where a fender was not used in good time
These minor damages do not affect the strength of the ship but they still have two major problems:
A 10 cms long bent section on a 20 meters long gangway stands out immediately and projects a low picture of the ship crew/company and owners to every visitor that boards the ship. The visitor starts with a negative note towards the ship.
A bent rail is itself a hazard. In the first place the rail was straight when we started off. The damage was caused – let us say, because of poor handling. The bent rail is not going to cause a disaster but it more than likely could cause an accident leading to more serious consequences.
We have seen therefore that minor damages have major effects. At the same time it can be said that; repair of minor damages on priority basis can bring in immediate benefits such as fewer chances of having accidents, safer, healthier & therefore happier crew. Even better benefits are to create a better impression of the ship.