Over the past two years the Marine Archaeology Unit of the Canadian Parks Service has been experimenting with the use of an electronic ranging and positioning system for three-dimensional archaeological mapping. This system (SHARPS) has been employed on three separate wreck sites with increasing degrees of recording complexity. An overview of this experience is given along with commentary on its effectiveness. Supplementary recording methods which have been required with the use of SHARPS are also outlined. A comparison of results using conventional hand mapping methods versus sonic recording is made on one specific site. Particular attention is paid to underwater set-up, data recording, and surface manipulation of the data in terms of time and cost effectiveness. Based on this information, future work with such equipment on selected sites is outlined with rationale as to which sites may be best suited to its use.