Admiralty & maritime expert witness Henry S. Woods, III has this to say on causation of maritime accidents:
Maritime accidents of all stripes – great and small – occur in a wide range of circumstances and conditions. The common thread that is usually found in the proper investigation and analysis of these accidents is not a sudden or mysterious failure of a system or item of equipment. Nor is it the lack of a properly functioning system or item of equipment. With the exception of product/vessel defects, the common cause of most maritime accidents are aspects of human error and human factors. The most crucial of these are:
maintaining a proper lookout,
observing a safe speed,
preserving night vision,
following the maritime Rules of the Road,
adhering to proper right-of-way rules,
the timely interpretation of aural and visual data, and maintaining a situational awareness.
In order for a vessel operator to successfully and safely perform such vessel operation tasks, he / she must possess and use normal aspects of memory, visual acuity, aural function, and human cognition. These are the most basic and important requirements of human performance in the various maritime operating environments.
For more see http://www.tridentmarinesafety.com/