International Maritime Organization, a United Nations agency that issues international regulations and standards for seaborne transportation.

Intermediate survey

The inspection of a vessel by a classification society surveyor which takes place between two and three years before and after each special survey for such vessel pursuant to the rules of international conventions and classification societies.

ISM Code

International Safety Management Code for the Safe Operation of Ships and for Pollution Prevention, which, among other things, requires vessel-owners to obtain a safety management certification for each vessel they manage.


International Security Code for Ports and Ships, which enacts measures to detect and prevent security threats to vessels and ports.