An Investigation of Ballast Water Management Methods with Particular Emphasis on the Risks of the Sequential Method

摘要

Ship owners, managers and builders will bernaware that a number of port states includingrnAustralia, Canada, Chile, Israel, New Zealandrnand the USA have introduced regulationsrnintended to prevent ships which arrive in theirrnwaters from discharging ballast water whichrncontains “non-native, harmful species of aquaticrnlife forms”. The masters of such ships arernexpected to demonstrate that they have takenrnsteps to prevent such discharge by some means,rnwhich is acceptable to the relevant port state.rnLR carried out an investigation on the variousrnballast water management methods withrnparticular emphasis on the risks of thernsequential method. LR, prompted by the factrnthat issues pertinent to the sequential methodrnhave not yet been fully appreciated by thernindustry, commenced a two-part study using 26rnexisting ships of various types, configurationsrnand sizes. The objective of the first part of thernstudy was to investigate the effects of thernsequential method on the ship’s structure andrnthe assessment criteria in respect ofrnclassification, statutory and operational aspects.rnThe objective of the second part of the studyrnwas the development of a safe operationalrnenvelope, on the basis of sea-keeping analysis,rnto control the dynamic effects for the ballastrncondition under consideration. Overall, thernstudy serves as a reference guide forrnAdministrations who intend to develop ballastrnwater management policies. The investigationrnraises serious concerns for the safety of mostrnexisting ship types and configurations using thernsequential method of ballast water exchange andrnoptions to mitigate such risks are discussed.