The Marine Region of the Hong Kong Police Force is responsible for policing the waters and 262 islands that lie within the 1,651 square kilometers of the Hong Kong Special Administrative Region (HKSAR). In addition to routine policing, the Marine Region has responsibilities in other diverse areas like quarantine, immigration, conservancy, and also port and maritime regulations (Hong Kong Police Force, 2005). The Region is now managing a police fleet of over 140 vessels of various classes. A modern police vessel is a complex, technologically advanced, and highly automated machine. As such, the Marine Region Support Bureau (MRSB) insisted that it must be maintained at the highest possible levels of operational availability while its life cycle operating and maintenance costs should be kept at a minimum. To achieve this aim, this article addresses the need to effectively implement a marine maintenance information system. Traditionally, the defects and maintenance data of the fleet were collected and recorded by the crew in writing, and then the maintenance records were used as the basis for maintenance decisions by the MRSB and the Hong Kong Government Dockyard. With the paper-based recording procedure, the following problems often occur: • There are missing data due to unintentional negligence or uncertainty about the nature of the equipment failure or damage, • errors occurred during the coding of failure information, and • there is difficulty in deciding whether repair tasks performed were routine servicing or corrective maintenance. To minimize such problems, it was decided that the processes of crew logbook entry and failure coding procedures would be replaced by direct input to the desktops of MRSB and the Government Dockyard through portable communication devices such as personal digital assistants (PDAs) and laptops, which can easily be obtained at reasonable costs locally. Currently, virtual private networks (VPNs) provide one of the most cost-effective ways for users to access organization networks while in Hong Kong waters. They are also an effective way of joining together the main office with remote depots using the public Internet. Three types of VPNs are being used. 1. Intranet VPN: This VPN can securely connect the desktops of the MRSB and the HKSAR Government Dockyard over the intranet, with all data traffic being encrypted. 2. Extranet VPN: Besides the functions provided by the intranet VPN, this network provides access to the MIS to preferred maintenance contractors. Data are accessible only over secure encrypted connections, with all contractor users authenticated. 3. Remote-Access VPN: For this network, authorized users are able to access the MRSB and HKSAR Government Dockyard MIS anytime from anywhere. With the aid of wireless PDAs, this facilitates decision making on the spot and is limited to decision makers such as the police superintendent. A preliminary attempt at developing a Web-based maintenance management information system was carried out for a small fleet of patrol vessels (Wong & Chan, 2002), and due to the nonmodular structure, a major difficulty was found in the modification and extension of the system framework. Recent advances in VPN technology indicate that VPN WANs (wide area networks) are now faster, cheaper, and more reliable than traditional WAN technologies. For a successful implementation of the IMIS, an efficient framework is needed to achieve the automaton of diagnostic processes and the integration of inspection and maintenance information under a secure communication infrastructure. Prior to an elaboration on the design of the proposed model, a brief review of object-oriented technologies (OOTs) is shown in the following section.