Safety

People are increasingly aware of safety issues in their daily lives and they are unwilling to accept levels of risk that might have been acceptable 50 or 100 years ago. The Titanic disaster brought home the fact that no ship is unsinkable, no matter how big. The loss of life in the Herald of Free Enterprise and the Estonia highlighted the potential dangers of designs which had large open deck spaces for the convenience of loading, and off loading, cars. This showed the danger that changes in design, as technology develops, can get ahead of the regulations intended to promote safety.

24 SHIP DESIGN

Efforts by the international community are beginning to improve the situation but the naval architect must not become complacent about safety. Some incidents such as those involving large tankers going aground and polluting the local shoreline hit the headlines. The general public, however, is usually unaware of unexplained ship losses, too often involving large and relatively new ships. The MV Derbyshire was such a case until the relatives and unions lobbied the government. Subsequent investigations and research led, amongst other things to the finding of the hull on the sea bed, to the tightening up of regulations concerning hatch covers and the acceptance that freak waves are not as rare as previously thought. In bulk carriers water ingress alarms are being fitted and so are double side hulls. Some ships are provided with hull stress monitoring systems involving strain gauges, pressure transducers and motion sensors. These help the master avoid undue straining of the hull at sea and during loading and unloading.

In recent years bulk carriers, tankers and Ro-Ro ships have received quite a lot of attention from the maritime community. Whilst still more needs to be done in those areas they are not the only causes for concern. Spouge (2003) pointed out that of losses of ships over 100 gross tonnage in the period 1995-2000, 42 per cent were general cargo ships and 25 per cent fishing vessels. The high rate of cargo ship loss is due in part to the greater number of these ships in service but if the loss rate per 1000 ship years is taken, figures of about 5.4, 3.3 and 1.5 are obtained for cargo ships, dry bulk carriers and oil tankers respectively.

The lessons to be learnt are:

(1) It is not just high profile ships that need the naval architect's attention. Cargo ships also accounted for 37 per cent of the fatalities in the cases of total ship loss over 100 gross tonnage.

(2) It is essential to analyse the data available on losses to detect trends and potential reasons for the losses so that corrective action can be taken.

Many, if not most, of the ships lost will have been built, maintained and manned in accord with the latest rules and regulations. It is clear that a ship can be designed to meet all existing regulations and yet not be as safe as it could, and should, be. This is partly due to:

(1) Regulations having to be agreed by many authorities. As such they are often a compromise between what is regarded by many as the best practice and what others feel to be unduly restrictive or are prepared to accept for economic reasons.

(2) The time lag between failures being experienced, analysed, the corrective action decided upon, agreed and implemented.

(3) Advancing technology and changing trade requirements leading to ships with new features, and operating patterns, which have not been fully proven. Testing of hydrodynamic or structural models, and of materials in representative conditions can help but the final proof of the soundness of a design is its performance at sea.

It must be accepted that ships cannot be made completely safe against all eventualities. Some measures to improve safety might:

(1) Make it virtually unusable. For instance too great a level of internal watertight sub-division, carried up high in the ship, would make it very difficult to move around or to stow cargo effectively.

(2) Be very costly, making the ship uneconomic to operate. It is this factor that makes many owners unwilling to do more than required. They fear competitors will do the minimum and get ships which are cheaper to own and operate. Fortunately some owners do recognize the need to do more than the legal minimum. They will benefit if their better safety record attracts shippers and passengers.

How To Have A Perfect Boating Experience

How To Have A Perfect Boating Experience

Lets start by identifying what exactly certain boats are. Sometimes the terminology can get lost on beginners, so well look at some of the most common boats and what theyre called. These boats are exactly what the name implies. They are meant to be used for fishing. Most fishing boats are powered by outboard motors, and many also have a trolling motor mounted on the bow. Bass boats can be made of aluminium or fibreglass.

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