Maritime safety is an issue of concern when operating a small to medium sized sailboat, and the appearance of hazards in the navigational route like floating logs can lead to a severe collision if undetected. As a precautionary measure to prevent such a collision with a log, a 2D vision-based detection system algorithm presented to detect these floating hazards. We take a combined approach involving predictive mapping by linear regression and saliency detection. The proposed method has been evaluated using precision and recall measures. The evaluation results show that the algorithm is robust and computationally non-intensive for future implementation of a real time on-board obstacle detection system for autonomous and computer-assisted sailboat navigation.