Methodologies to determine, evaluate, and implement prospective measures for preventing marine collisions and groundings are presented. The use of cost-benefit analysis to evaluate prospective safety measures is emphasized. <p> Prospective safety measures are represented as changes to variables that relate to the life-cycle of an oil tanker. Most of these variables, such as crew size and training, are associated with the operational phase. A systems engineering approach was used to develop a causal diagram which models the influence of these variables on a tanker's accident risk and profitability. <p> The practical application of cost-benefit analysis to evaluate prospective safety measures is examined. The benefit of a specific safety measure is presented as the reduction of accident risk derived by implementing that measure. Since human factors play a significant role in most marine collisions and groundings, a risk analysis of these accidents is largely a human reliability analysis. A human reliability analysis is a special case of risk analysis, which emphasizes human factors. <p> The necessity of suitable data for conducting human reliability analyses of tanker navigation is discussed. Recommendations are offered to improve the quantity, quality, and availability of such data. <p> The current economic climate inhibits the implementation of safety measures in excess of established minimum requirements. Reforms of marine insurance practices to promote greater implementation of safety measures are presented. These reforms create financial incentives by firmly linking the cost of insurance to accident risk. / Master of Engineering