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compromise between safety, economics, and risk. To give an extreme example, a vessel cannot be designed to withstand 300-foot-high waves; it would be impractical to build and not economical to operate. Moreover, the probability of encountering such a wave is virtually nil. On the other hand, there is sufficient evidence to conclude that 66-foot-high waves can be experienced in the 25-year lifetime of oceangoing vessels, and that 98-foot-high waves are less likely but not out of the question. Therefore, a design criterion based on 36-foot-high waves seems inadequate when the risk of losing crew and cargo is considered. IACS Recommendation 34 should be modified so that the minimum design wave height is at least 65 feet. The dynamic force of wave impacts should also be included in the structural analysis (as opposed to relying on static or quasi-dynamic analyses).
Good vessel maintenance is equally important, particularly to prevent corrosion of hulls and vital structural elements. Saltwater corrosion eats away unprotected steel, reducing its strength—a phenomenon ship surveyors call “wastage.” In 1960, the tanker vessel Pine Ridge was surveyed and given clearance to sail, even though wastage in key structural members ranged from 25 to 60 percent, meaning that the thickness of vital parts of the ship was only 25 to 60 percent of the original design value. Today, with thinner sections and less steel in modern vessels, careful maintenance and inspection are vital to control wastage. Could a modern vessel with 60 percent wastage survive a gale, let alone a serious storm? In 1960, the tanker Pine Ridge could not; she broke in half, and seven crew members, including the master, lost their lives.
In the coming decade the world’s shipyards will be busy fulfilling orders for new tankers to replace the old single-hull vessels that must be withdrawn from service, as well as building more bulk carriers, building more and larger container ships, and building even larger passenger vessels. With fewer vessels overall in the merchant fleet, and with replacement vessels being more costly but more economical to operate, there is a benefit to be gained by investing in more robust designs, better safety equipment, more extensive crew training, improved weather instrumentation and weather routing, and conducting inspection and maintenance to rigorous standards. This opportunity to improve the safety and reliability of merchant vessels should not be lost.