Article - Issue 13, August 2002
Shipping safety – A matter of concern
Douglas Faulkner FREng
A matter of concern
Some newer ships such as the Stena Vision here are designed with safety and reduction of pollution in mind, but with a steadily ageing world shipping fleet and declining standards of maintenance, there is increasing concern about ship safety. The issues involved are considered here and some suggestions are given for implementing improved shipping safety.
Air travel may be the fastest growing transport mode (Ingenia, August 2001, Issue 9) but in terms of cost per tonne mile shipping at about £0.25 per tonne mile is an order of magnitude more efficient than road transport and two orders more efficient than air freight. Ships therefore continue to carry around 95% of international freight, compared with about 0.5% for air freight. It follows that shipping remains the most important transport mode for the world’s economic and social wellbeing. Future demands from the developing countries will place an increasing load on shipping, which is a slow and reactive industry. Even today, real technical and human issues of ship safety exist, which are not being adequately addressed. This article briefly reviews the present position and possible future scenarios for improvement.
Indicative shipping data and projected growth
Available statistics on ships (and ship safety) can vary significantly, hence the first adjective above. Table 1 is derived mainly from the British Chamber of Shipping data for the world fleet and from the widely used Fearnleys’ Annual Review 2001 for sea borne trade. Values for the year 2000 have been collectively adjusted into three cargo and ship types, hopefully to make the data more understandable.
From Table 1 we see that the dry and liquid bulk carrying ships, the ‘work horses’ of the sea, make up 40% of the trading fleet but carry 66% of world trade, which reflects their greater ship size dictated by the economies of scale. Manufactured goods are said to represent nearly 20% of world trade. Not seen in Table 1 is the average ship journey of about 4,500 miles; and the UK owned fleet is about 1.5% of the total but it carries about 4.5% of world freight – a pale shadow of its former glory, mainly due to successive UK governments’ lack of commitment to UK shipping.
Between 1982 and 2000 world trade increased by 2.8% per annum. A 2000 projection suggested that world trade would double in the next 12 years, which is equivalent to about 6% p.a. growth. Some may regard this as unlikely, but there is little doubt that the increasing demands and trade from China and the more rapidly developing countries will provide an engine for increased shipping growth, and this at a time when the world fleet is getting steadily older and standards of maintenance and training are declining. Such growth implies a need for more ships, berths, trained seamen, etc. This will have adverse effects on shipping safety unless standards improve.
Shipping casualties and causes
Statistics on ship losses at sea or inshore are detailed and impressive, but the vital feedback data to establish their causes is unimpressive and needs to be improved. In the last two decades average loss rates for individual trading ship types have varied between about 0.55% p.a. to 0.15% p.a. with an overall average of about 0.30% p.a. Crew loss data is harder to find but it appears to exceed a thousand seafarers each year. Such loss rates would be unacceptable in other transport systems where lives are at risk. The usual shipping defence is that loss rates are reducing and that lives of the travelling public are not at risk, implying no concern for seafarers.
However, it is not just loss of life which causes concern. Because the vast majority of the world’s trade is carried by sea it is the total loss of ships, their high value cargo and lives that is unacceptable and should concern us all. (Also, see later references to ‘public confidence’.) In particular, the industry has recently become concerned about the increasing loss of large bulk carriers, which reached a peak in 1991 for ships weighing over 10,000 dwt (dead weight tonnes) of 22 ships lost and a cost of nearly 200 lives. A broad breakdown (within 5% bands) from two comparable sources of the main causes of bulker losses over the last two decades is:
Operational causes: %
- Fire and explosions 20
- Collisions and groundings 35
- Machinery damage 5
Design and maintenance causes:
- Water ingress 40
- Hull breaking in two (at sea) 0
- Capsize of intact ship 0
‘Water ingress’ and its progression through the ship to cause it to sink is entirely due to inadequate structural design and/or poor maintenance. The first can so easily be put right if a survival design approach is adopted (see later).
Speaking generally for all shipping, attributable ship loss causes from various sources, including insurers’ data, break down to over 30% due to bad weather and about 25% due to ‘other’ unexplained causes. The Secretary General of the International Maritime Organisation has stated that this is unacceptable. It follows that ships are simply not being designed to survive sufficiently extreme weather. Figure 2 shows a cape-size bulk carrier Selkirk Settler whose upper deck is being swamped by a huge wave crest in the mid north Atlantic in February 1987. Had she had normal strength hatch covers she would not have survived. That same storm sank two ships and severely damaged three others.
What is generally agreed is that about 80% of marine accidents arise from human errors of one sort or another, mainly in operating ships. Their consequential costs are said to run into billions of US dollars each year. An extreme example of quite inadequate design of container securing and protection arrangements is provided in Figure 3. Seven hundred containers from four large container ships were swept overboard and many more were smashed by huge waves on the beam in October 1998 in the north Pacific. The cargo loss and damage alone was said to cost more than $3 billion.
Some industry weaknesses In 1836, following three years in which 1702 British ships and 1714 lives were lost, a House of Commons Select Committee into The Causes of Shipwrecks concluded that the most frequent and generally admitted causes were:
defective construction of ships
inadequacy of equipment
imperfect state of repair *
improper or excessive loading *
inappropriateness of form *
incompetence of masters and officers *
drunkenness of officers and men
operation of marine insurance *
want of harbours of refuge *
imperfection of charts.
It is sobering to observe (*) that six of these causes are still relevant today! Indeed, today we should admit to inadequate design for extreme storms and also add ‘mariners’ fatigue’, which has reached alarming levels.
So, what is wrong with the shipping industry? Since Samuel Plimsoll’s day and from a survey of more recent opinions it seems that:
things still move very slowly
concern is bred of catastrophes
solutions are rarely acted upon
unwelcome events are generally suppressed
profit is valued before safety
malpractices are not rare
there are too many (and mainly prescriptive) regulations
ship rules are not transparent, have no commentary and often reflect what is acceptable, not what is needed
design ‘modelling’ of extreme loads and ship component strength is generally flawed and is often unsafe
irrational tonnage rules are still used, some of which are unsafe
regulations are not always sufficient to enforce standards
education and research need a fresh look
there is too much tonnage chasing too little cargo
weather routing (avoidance) is a weak crutch
corporate and personal liability barely exist
ship insurance provides a convenient cover.
In a single sentence, the industry is too complacent, turns a blind eye, is reactive more than proactive, and has a generally inadequate safety culture. It should manage safety risks with the same care and attention as it manages financial risks.
This has led to ‘ships of shame’ (the tanker Erika (1999) was a good example, as are many bulker losses) and to declining standards. A recent inquiry into ship safety by the International Commission on Shipping (ICONS) provides evidence of abuses, exploitations and injustices to seafarers, who often have to operate substandard ships in appalling conditions.
At present the responsibility for substandard ships rests mainly with ship classification societies (CSs). Moreover, they are not independent arbiters of safety. Theirs is a competitive business which relies on pleasing their customers, the ship owners and operators. Despite the undoubted improvements they have made to ship safety, the International Association of Classification Societies (IACS) continues to be widely criticised, to the extent that calls have arisen recently for an independent ‘super IACS’ to pool the best talent. IACS suffers from lack of effective leadership (the Chairman changes every year) and is still too reactive and inward looking.
The importance of public confidence
The loss of public confidence always arises when major incidents and loss of public life occur, like the Titanic (1912) and the more recent ro–ro ships Herald of Free Enterprise (1987) and the Estonia (1994). Moreover, you cannot insure against loss of public confidence. Should this happen, for example, in the rapidly expanding cruise ship market (which has had a 60% growth in the last ten years), there could be a major downturn in the market.
It is precisely for such reasons that the very near loss of the specialised Antarctic cruise ship Bremen in the south Atlantic in February 2001 has been kept under wraps. She was struck by a monster wave over 30 m high; the small cruise ship Caledonian Star (March 2001) was caught in similar circumstances. Three other much larger cruise ships have been similarly struck by abnormal waves in recent years and detailed circumstances were generally withheld as only two passengers were lost overboard. ‘Near misses’ such as these should receive full attention and research study as is done in the aircraft industry.
The ro–ro ship Estonia’s rapid loss with 852 lives in September 1994 caused public concern and justifiable fears about the rapidity of the final capsize and the inability to evacuate the passengers in the statutory time of 30 minutes (see The Royal Academy of Engineering news release of 6 January 1995). The official investigation report has been widely criticised and it seems the most likely cause of the loss has not been properly established – a not uncommon failing of official reports.
The mammoth cruise liners of today, accommodating up to 4,000 passengers, could not be evacuated in 30 minutes if there was danger from fire or sinking. Cruise passengers at large are doubtless unaware of these incidents and facts, and it seems that public confidence in cruising has so far not been dented. The safety of many thousands of people who daily use ferries is also at stake. Ferry speeds are increasing, which escalates the risks.
Moreover, there is also a wider public concern which needs to be remedied regarding oil pollution, mainly from tanker spills. The general tolerance of governments and of the public to accept pollution has evaporated. Reduced pollution, of course, is also directly linked to improved shipping safety. Stena Line’s answer to stop pollution is seen in Figure 4. This shows a giant 358,000 m3 capacity tanker of 70 m beam whose safety features include double hull construction and, for breakdown redundancy, twin independent engines, twin propellers, steering gears and rudders. It can also maintain 6 knots on one engine in force 8 head seas.
Recent actions and improvement suggestions
The International Maritime Organization
The IMO is the international body responsible for safety of life at sea (SOLAS Convention) and has over 150 member states. Under the inspired leadership of William O’Neil CM FREng, its Secretary General, IMO recognises some of the above weaknesses and has recently implemented several measures aimed at reducing human errors in ship operation. Most notably they include the International Safety Management (ISM) code and the Standards of Training, Certification & Watchkeeping (STCW) convention. The industry seems to be responding reasonably well to the additional paperwork and to the inevitable teething problems.
At present IMO is also very concerned with bulk carrier safety. It is introducing a formal safety assessment (FSA) approach to ship design and operation, starting with bulk carriers. It seems to follow on similar lines to the practice in the offshore industries. The author used an FSA approach for the forensic analysis of the loss of the Derbyshire and has suggested guidelines for use when investigating ship casualties. The underwater technology now exists for examining important shipwrecks at close quarters.
A European Maritime Safety Agency
There is a substantial loss of confidence in the shipping industry’s ability to regulate and then to implement. Moreover, it is essentially self regulating, which provides an in-built tendency to abuse the trust placed in it by governments and the public. It is therefore important that regulation should be undertaken by a truly independent body. Such a body for the aviation industry in the UK is the Civil Aviation Authority, ably supplied with feedback from the Air Accident Investigation Branch. (The UK already has a Marine Accident Investigation Branch as part of the Department of Transport.) The CAA is now being superseded by the European Joint Airworthiness Requirements.
At the first European Parliamentary Symposium on Maritime Safety, on 24 January 2002, it was suggested that an independent Maritime Safety Agency be established in Europe. Its terms of reference have yet to be agreed, but if it is to be styled on the European Joint Airworthiness Requirements then it will need ‘teeth’ to be able to influence and co-operate with IMO, IACS and the various ship class societies. This authority could come from the IMO, in which case provisional terms of reference and responsibilities for further discussion are suggested: to identify design, construction and maintenance areas where provision of technical safety is shown to be inadequate; to formulate or change corrective technical regulations and, when agreed, sample check that they are being properly implemented.
This is naturally a delicate matter because it will, initially at least, be seen by IACS as undermining its authority. But, if the situation is properly handled, IACS should realise it is being assisted to do its job more effectively in the interests of shipping safety internationally. This should then also answer much of the criticism which IACS at present suffers, and thereby strengthen its position.
Legislating for human and operational weaknesses is a vast task requiring widespread efforts, but with the main thrusts coming from the IMO, owners and operators. Better technical feedback from sea, together with more resources, is needed for the MAIB to provide a more effective service worldwide. European funds could perhaps be forthcoming to build it into a European MAIB closely linked to the EMSA. Survival Design and ‘MaxWave’ Because of insufficient forethought and testing, major accidents at sea in recent years have led to reactive modifications to the design of tankers, bulk carriers and ro–ro ships. It is abundantly evident that ships are not at present designed to have sufficient capability to survive the worst storms that nature can brew. This is quite contrary to the logical extreme ultimate limit state design approach as practised for naval, civil and aircraft structures. For example, William O’Neil points out that bridges are not built expecting that they will collapse if they are exposed to certain weather conditions.
With this in mind, and following his work for the Derbyshire investigation, the author was invited by the World Meteorology Organization and others to present a keynote address to the metocean community on what naval architects needed in terms of extreme wave measurements from satellites and other remote sensing devices. This led in December 2000 to a three year, 4.65 million euros European research programme, ‘MaxWave’, comprising ten projects in six countries. Already the programme is providing better data on the characteristics of waves in extreme storms. The first year’s evidence shows that very large waves do occur with wave heights of 2.3 to 2.5 times the significant wave height (Hs), and one was 2.9 Hs. These far exceed the smaller linear waves used at present in design. These data, together with evidence of losses and near misses from ships at sea mentioned earlier, will surely provide the need for survival design. Moreover, corresponding critical ship conditions are being identified and there is now little doubt that ships can be designed with relatively low first cost penalty to withstand most of the effects of abnormal waves, thereby saving lives and property at sea.
Survival Design illustrated
The most important step in a first generation survival design approach is to determine the characteristics of the most likely damaging survival wave or sequence of waves for the mode of ship loss being considered. For example, to estimate the survival design forces on forward cargo hatch covers and their side coamings in bulk carriers the following procedure, based on the Derbyshire research, has been recommended:
select a survival storm in terms of the significant wave height Hs as a function of ship length and type
this wave should approach limiting steepness conditions just before wave breaking, defined by its peak period Tp = v(13Hs); for Derbyshire this leads to a most probable wavelength of 294 m, which is close to her 284 m length and ensures extreme pitching motions
a maximum extreme wave height of 2.5Hs is recommended, with a severe wave crest to wave height ratio of about 0.65 to 0.7 (recent measurements have reached 0.74); this is particularly important for wave impact loads on vertical structure and fittings.
Non-linear wave and ship response theory is then applied, preferably also checked by high quality tank measurements, over a range of nearby wave periods to establish the conditions for maximum relative motions and maximum pressure on the hatch covers being considered. This leads to required improvements in hatch cover strength of between 2 and 3.5 times the present standards to effectively eliminate the weakness.
Recent ship damage and developments in horizontal wave impact theory have shown that present ship rules are ‘an order of magnitude inadequate’ (a recent Health &Safety Executive report). This huge gap arises from three sources which are not presently considered:
insufficient wave height and crest elevation
no allowance for near breaking wave crests reaching velocities up to two times that of the wave
insufficient consideration of water impact coefficients.
This has led to many failures and losses of deck equipment (including the loss of the 21 ton starboard windlass on the foredeck of Derbyshire), damage to bridge fronts and bursting of bridge windows (25 m or more above sea level), damage to bulwarks, hatch coamings and to ships’ sides in bulkers and tankers, etc. The procedure outlined above illustrates a survival approach to prevent or considerably reduce such damage.
A similar survival design approach has been advanced by William Buckley to improve ship capsize resistance. It is sobering to recall that the Queen Mary nearly capsized in the Western approaches with 15,000 American troops in 1942 when struck on the beam by a long crested elevated wave which rolled her to just short of her vanishing stability limit.
Implementing ship safety improvements
Other political rocks ahead are that not every classification society or flag of convenience country will fall in line with anything that costs money, plus the long tail of substandard ships to be worked through. Ideally, to overcome this, international legislation is required. Failing this, EU ports could consider adopting tough docking approval criteria to prevent use of port facilities by shipowners/operators who do not comply with new tougher safety requirements. Whilst IMO’s present proactive stance to improve ship safety is unlikely to impede an agreed survival approach to design, the same cannot be said of the present understandably cautious stance of IACS. High level intervention is being considered to ensure this new knowledge (when validated) is implemented sensibly in ship design and operation. It would also help to ensure that the MaxWave research and development may continue to provide further data.
Some present and future ship trends
Cruise market ships are increasing in size. The French-built Queen Mary 2 will be twice the gross tonnage of Queen Elizabeth 2. The World, recently built in Norway, is the first residential apartment cruise ship. This floating ‘resort’ offers 110 luxury spacious residences ranging from 335 m2 to 975 m2, as well as 88 guest suites for rental. The World is scheduled to visit 46 countries, and will spend 250 days in port each year at such events as the Monaco Grand Prix, Cannes Film Festival, the British Open (which it visited this year) and the Americas Cup.
Container ships now dominate the dry cargo trades and continue to grow in size. Among the largest are P&O Nedlloyd’s 6802 TEU (20 foot equivalent units) trans-Pacific ships. A design for a 330 m long × 46 m beam 9,000 TEU design is being developed by Daewoo in anticipation of Chinese interest. Meanwhile, IHI and others anticipate a generation of 10,000 TEU ships, and P&O’s new container port on the Thames is being designed to handle this size. A remarkable concept of a 15,000 TEU ship of 69 m beam and 28–30 knots has recently been reported.
Over the past decade, high speed cruise-ferry ships have become popular, notably in Europe. Many superfast ro–pax ferries have entered service, typically powered by large propeller drives developing 40–60 MW to give 28 knots. Figure 5 shows a 38 knot monohull ro–pax ferry with T-hydrofoils fore and aft and 4 lateral fins for roll control. Electric drive is to 4 Lips steerable water jets under the transom stern. Meanwhile, Japan plans a 49 knot hydrofoil assisted techno-superliner.
Larger ocean going fast ships have yet to be proven. Nevertheless, a 40 knot multiple gas turbine ship with five 50 MW water jets is due to start trans-Atlantic service next year. A trans- Pacific concept of a foil assisted semi- SWATH container ship (small water-plane area twin hull) capable of 64 knots is being considered.
There must be some anxiety about such developments since increased ship speed and/or size increase the risk of heavy weather damage, especially in open ocean conditions where abnormal steep elevated waves are most likely to occur.
In the eyes of many, the international shipping industry is in danger of falling into disrepute with its continuing malpractices and slow, reactive responses, including responses to calls for safety related changes and to related research and development initiatives. There is also evidence of the industry’s exploitations, abuses and other injustices to its seafarers who risk their lives, often in substandard ships in appalling conditions. This should be unacceptable at any time, but ships carry about 95% of the world’s raw materials, food and consumer goods, which underpins the world’s economy. At the same time, it is quite possible that shipping freight may double in the next 12 years or so to meet the increasing demands from developing countries, and safety is then likely to worsen.
If these concerns were not enough, exciting new developments in vessel type and form, in power plants, transmissions and in propulsor types are leading to larger and faster ships. These two trends of size and speed inevitably increase the risk of heavy weather damage, especially to unrestricted operation ships in open ocean conditions where the most damaging abnormally large, steep and elevated waves occur more often.
It is evident that ships are not presently designed for sufficiently extreme rough weather. The Secretary General of IMO finds this to be unacceptable. Mariners deserve better, and we underestimate the power of the sea at their peril. Putting this right would more than repay the extra costs to ship owners and operators.
This article attempts to show how this may be achieved by establishing a survival design approach for critical ship conditions based on improved metocean data arising from the current EC MaxWave research and development programme. Wave impact design loads for ship fittings and structure are ‘an order of magnitude inadequate’, and serious doubts exist in relation to ship hull bending and ship capsize. These therefore become priority topics for the first phase of survival design.
Before Survival Design and MaxWave’s findings can be implemented, IACS in particular needs to be convinced of the need to consider changes to some of its rules. Much evidence for this is already available to demonstrate the need for survival design. With this in mind, the author and MaxWave leaders are planning a high level meeting at IMO around October 2002 at which they intend to stress the importance of the MaxWave work and survival design as a major engineering step towards establishing a much needed, more proactive and visionary safety culture in shipping. This would be in everyone’s interest.
AAIB Air Accident Investigation Branch
CAA Civil Aviation Authority
EMAS European Maritime Safety Agency
FSA Formal Safety Assessment
IACS International Association of Classification Societies
ICONS International Commission on Shipping
IMO International Maritime Organization
ISM International Safety Management
JAR (European) Joint Airworthiness Requirements
MAIB Marine Accident Investigation Branch
SOLAS safety of life at sea
STCW Standards of Training, Certification & Watchkeeping
SWATH small waterplane area twin hull
TEU 20 foot equivalent units
Douglas Faulkner FREng
Emeritus Professor of Naval Architecture & Ocean Engineering, University of Glasgow
Douglas Faulkner has enjoyed two careers. The first involved designing and maintaining ships for the Royal Navy, his most responsible task being to verify the pressure hull design and to conduct the deep dive trials of HMSM Dreadnought, the navy’s first nuclear submarine. In 1973 he was appointed to the John Elder Chair of Naval Architecture at Glasgow where he pioneered a new and more efficient approach to the structural design of large stiffened cylindrical components of floating offshore structures. He retired in 1995 and worked with Lord Donaldson in resolving the cause of the mysterious loss without trace of the huge bulk carrier MV Derbyshire. Among his many awards and distinctions he has gained the highest accolades for naval architects from the USA, USSR and UK.