January 28, 2005

Union says ships should be designed to cope with giant waves

With mounting evidence that "rogue" waves are on the increase, British maritime union NUMAST (National Union of Marine, Aviation and Shipping Transport Officers) says large waves should no longer be considered "freak"--and ships should be designed to cope with them.

Speaking at a Royal Institution of Naval Architects conference on "Design and Operation for Abnormal Conditions," NUMAST senior national secretary Allan Graveson recalled his personal experience of a so-called "freak wave" in the North Pacific in 1986, when 158 items onboard his vessel were damaged by a massive wave that broke over the ship. "This was the only time I have experienced real fear," he said.

Graveson told the conference that technology has proven that freak waves exist and there is increasing evidence of their frequency and magnitude. In the face of this evidence, NUMAST believes ships should be routinely built to withstand abnormal waves.

He argued the need for a change in terminology. Terms such as "rogue," "freak" and "extreme" have been used to describe large waves.

"These words," said Graveson, "conjure up something almost mystical, something that is so unusual that we have to accept the inevitable. The implication is that nothing can be done: it is a 'peril of the sea' to which we must reconcile ourselves."

"The term 'freak' has long since disappeared from vocabulary of the medical profession," Graveson argued. "Advances in medical science mean conditions formerly described as 'freak' are now considered in terms of their relative frequency and severity, and described with the less emotionally-charged term 'abnormal.' We should follow this example in our own industry and put abnormal waves in their rightful place--as part of a continuum of wave size and power."

Graveson told the conference that there is no escaping the need to address shipbuilding practices.

"We are currently in a position where ships are actually becoming less, not more,robust," he said.

"The movement to a goal- or risk-based system of design from that of a prescriptive rule-based one has opened the door to non-standard watertight compartments," he said. "Alternative design arrangements said to be of equivalence can put revenue-earning capacity and aesthetic appearance before safety. Unless account is truly taken of all the likely risks, including abnormal waves, severe damage and losses are likely to occur with increased frequency."

NUMAST sees an urgent need for a set of uniform rules of construction applicable to all types of vessel, and these should take account of protection against abnormal waves.

Warning of "perilously slow" progress on the issue, Graveson argued that solutions need not be expensive. "Improvements in ship design and construction should save on repair costs, increase second-hand value and improve life expectancy--both of ships and seafarers," he said.

"We should remember," said Graveson, that, "in the event of significant loss of life, or a major pollution incident, the media and public would not accept the excuse that 'it was the wrong type of wave'--especially when there is increasing evidence that these waves not only exist but, thanks to climate change, are occurring with increasing frequency and ferocity. Politicians would have to act in such circumstances."

"The principle of taking preventative action remains alien to this industry," declared Graveson. "A cultural change is needed and the benefits of advanced measured action should be demonstrated over reactionary 'knee-jerk' regulation."

For more on "monster waves" read this European Space Agency article

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