The recent casualty in Louisiana involving a container ship and an offshore service vessel along with vessel/bridge collisions in other states, bring to the forefront the importance of presumptions in maritime law. Presumptions in the law can be powerful tools and can be difficult to overcome.
Perhaps one of the best-known examples of a presumption arises when a vessel collides with a fixed object. When two vessels collide, admiralty law refers to that as a “collision.” When a vessel strikes an object that is fixed, such as a bridge, buoy, or pier, an “allision” occurs. When a vessel strikes a fixed object, such as a railroad bridge, the moving vessel is presumed to be at fault and the burden shifts to the vessel to introduce evidence to indicate just what caused the allision. This presumption may not apply, in limited circumstances, if the offending vessel can show that the allision was caused by an act of God.
In a tug-tow situation, the tug is presumed to have the “dominant mind,” since it normally has control over the tow. The “dominant mind” doctrine generally places liability on the tug, absolving the tow from liability since the tug is the vessel actually in control of the operation and supplies the power to move the tow. When a tug causes the tow to collide with another vessel, the tug is presumed to be at fault unless the tug can show otherwise. On occasion the tow has been held liable where the tow’s personnel were in control of the operation.
Occasionally a moving vessel that collides with a stationary object can be exonerated from liability if the vessel can show that the allision was the fault of the stationary object or that the allision was an unavoidable accident.
The U.S. Supreme Court established another presumption in the 19th century in the Pennsylvania decision. If a vessel at the time of collision is violating a statutory rule of navigation, that vessel is presumed to be at fault and the burden shifts to that vessel to prove otherwise.
The importance of always being in compliance with the rules of the road and other statutory requirements cannot be overemphasized, since many presumptions, once established, are extremely difficult to overcome.