Marine simulation systems have been introduced in maritime education and training to foster the qualified and competent personnel for working in the maritime industry both afloat and ashore. However, there are many problems with most marine simulation systems today: the long development cycle, the high expenditure, the limited accessibility, the difficult maintenance, and the absence of customization etc. Web-based maritime training environment tries to solve these problems, and still allow very realistic and high-interactive marine simulations, delivered and edited via the Web. This paper presents modeling and system design for a Web-based maritime training environment to facilitate online simulation training from anywhere, anytime.