Abstract: Systems and methods for monitoring complex transactions, such as international physical oil and petroleum trading and shipping transactions are disclosed. The disclosed systems include equipment installed on a vessel, such as a tanker, configured to monitor the quality and quantity of oil loaded onto and discharged from the vessel. The system also includes a remote data center configured to receive the cargo information from the vessel-board equipment. The remote data center is also configured to securely maintain information and documents generated during the transaction, such as financial documents, quality and quantity reports, bills of lading, and the like. The system provides a portal whereby stakeholders in the transaction can monitor all aspects of the transaction.