The term ‘in transit’ relates to all times when the installation is not at or in the immediate vicinity of its first, a previous or its new working station. It is intended to exclude installations from the Regulations when the primary risks are marine. Manoeuvring in preparation for leaving a station or after arrival to position the installation is not part of transit, ie the Regulations do apply to such manoeuvring.
Source: A Guide to the Offshore Installations and Pipelines Works (Management and Administration) Regulations 1995, Guidance on Regulations (UK HSE L70), Second Edition, 2002. Regulatory Guidance