Tanker grounding frequency and spills in the Finnish Gulf of Finland

Groundings and ship collisions are the two most frequent accident types in the Gulf of Finland, which in the past decades has seen an increase in tanker traffic. This has mainly been oil transport from Russia. Both accident types pose a major hazard to the marine ecosystem, as spills of catastrophic magnitude can occur as a consequence. In order to better plan for the response to and/or prevention of accidents, the frequency and size of spills should be known. This paper estimates the expected number of tanker groundings of different tanker types for the busiest tanker ports in the Finnish part of the Gulf of Finland. Furthermore, in this paper statistics of the sizes of chemical, gas and oil tankers visiting Finnish ports is presented. Finally, the expected number and size of spills is estimated based on the expected number of groundings and the tanker sizes using a spill model based on tanker deadweight (DWT).