much energy as a wave 25 feet high, and a wave 100 feet high has 16 times the energy. A vessel designed for 25-foot-high seas might not be able to withstand the tremendous forces imposed by extreme waves—forces that can collapse hatch covers, buckle hull plates, or even break the back of the vessel.

  • There is no single, internationally accepted standard-making body for ship design, no uniform set of rules. Instead, rules are promulgated by various classification societies for each type of vessel, and each classification society has its own set of rules. Design loadings are generally expressed in engineering terms, and it is not clear what sea state they are based on. From the sample I’ve been able to review, it appears that a sea state with 35-foot-high waves is the norm.10 In light of current knowledge, this is inadequate. I would not want to serve on a 900-foot-long vessel built to these standards and routinely traversing the Gulf Stream, or the Agulhas or Kuroshio currents.

  • A secondary conclusion is that the masters of vessels designed in accordance with the older standards need to know the capability of their ships and need to have the authority to avoid those waters where there is a higher probability of encountering extreme waves. Requiring a rigid adherence to schedule and route may cause the vessel and crew to be endangered needlessly.

  • Finally, if the vessel is not properly maintained, there is no telling what kind of seas she will be able to withstand if put to the ultimate test. Normal practice is dry dock every five years, at which time the vessel is supposed to be inspected for cracks and damage due to corrosion. Older vessels frequently had hull plates that were 1 inch thick. Given today’s high-strength steels, the thickness has been reduced in many cases to 0.4 inches. In addition, new epoxy paints provide better corrosion protection.11 But if defects in the epoxy paint are not detected and repaired, the margin of safety for corrosion damage is less than it used to be.


The first line of defense against extreme waves is never to encounter one. While there is no absolute guarantee that this can be done, mari-

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