once goods leave the port (or place) of loading, they will be carried to the port (or place) of destination over the usual or most common route without undue delay or interruption, otherwise the insurance cover may be voided. In practice, however, marine insurance policies provide for some delay or interruption, especially those beyond the control of the insured party.
Read more: http://www.businessdictionary.com/definition/in-transit.html#ixzz3kHqH5PG4