Recent advances in communications technologies enable access to the Internet from anywhere in the world. This has generated interest, demand and research into methods of using and enhancing this technology to deliver Continuing Professional Development (CPD). This research examines issues relevant to the electronic delivery of professional updating to marine engineers in a pro-active manner locating the learner at the centre of the CPD process. Educational theories including experiential learning, andragogy, constructivism and Laurillard's conversational framework are investigated and the importance of learning styles in the design of material based on user needs is examined. A needs analysis of 1117 marine engineers revealed which subjects were in most demand for CPD and showed that individuals have different learning requirements. An accompanying survey of learning styles showed the respondents to be strong reflector/theorists but indicated that learning designed to be effective for all styles would be most appropriate. The conclusions drawn from the review of CPD, Internet and educational theory were combined with the results of the survey to derive the principles necessary for the creation of an innovative approach to online learning. The outcome was the synthesis, development and construction of the Marine Engineers' Managed Environment for Learning (MEMEL); an Internet based learning environment for the delivery of CPD to marine engineers. MEMEL has the ability to deliver online learning to a variety of learners on a range of subjects. As the evaluation of managed environments for learning is a comparatively new undertaking it was necessary to develop a novel framework specifically for the purpose. The evaluation indicated that MEMEL is a valid vehicle for the delivery of online learning. Two areas that have been specifically identified for further research are the use of electronic media to facilitate the process of reflection and enhancing access for users with a disability.