When one thinks of admiralty law the archetypical fact pattern that comes to many people�s minds is a collision or allision (vessel contact with a fixed object). There are many well ingrained legal concepts and rules, some of which are unlike anything found in land based law.

First, when there has been a collision or allision the vessel herself may be sued as if she were a person. This is an "in rem" action and the complaint is against the vessel her tackle her engines and appurtenances.

Second, under general maritime law, each vessel must pay in proportion to the amount that it was at fault. This rule stands in stark contrast to state law in a those states, including Maryland, where plaintiffs who bear any fault can be barred from all recovery.

Third, there are several judicial presumptions of fault that all vessel operators should bear in mind. A vessel creating wake is presumed at fault for damage caused by wave wash. A vessel in violation of any safety statute which could have prevented the casualty is presumed at fault. A vessel that is drifting or dragging anchor is presumed at fault. A vessel that allides with a fixed object (unless it is submerged) is presumed at fault.

Fourth, there are several sources of fault in addition to the judicial presumptions including, statutory violations, local rules, unseaworthiness of your vessel and custom. If you violate a custom you may well find yourself liable for the casualty. A prime example of a custom is the Point Bend Custom on the Mississippi River. Since the current flows fastest on the outside of a bend and slower under a point of land, all downbound traffic travels around the outside of a bend while upriver traffic takes advantage of reduced current by traveling from point of land to point of land. This creates a situation in which large vessels must weave through each other's paths.