River is absolutely correct. Admiralty courts almost never assign full blame to just one vessel involved in a collision. The reason can be found in the International Regulations for Preventing Collisions at Sea known as the COLREGS (http://www.navcen.uscg.gov/pdf/navRules/navrules.pdf). The rules ...

For two power driven vessels the vessel having the other vessel in the forward starboard quadrant is the give way vessel (required to change course and/or speed to avoid collision) and the other is the stand on vessel (required to hold course and speed - until evident that collision is imminent). If ...