Admiralty is a separate jurisdiction.  However, admiralty courts are not separate judicial bodies.  Although federal district courts are vested with original jurisdiction in admiralty and maritime causes, they cannot sit both as a court of law and as a court of admiralty at the same time and in the same cause.  Jurisdiction over legal and admiralty matters is different from each other as if they are vested in different tribunals.

Generally, admiralty cases are tried without a jury.  A district court sitting as an admiralty court has general jurisdiction of all causes of admiralty and maritime jurisdiction, without considering the sum or value of the matter in controversy, or to diversity of citizenship.  Therefore the distinction between admiralty and such other bases of federal jurisdiction as diversity or federal question jurisdiction stands very important.

In Defense Plant Corp. v. United States Barge Lines, Inc., 145 F.2d 766 (2d Cir. N.Y. 1944), the denial of intervention of appellants in an admiralty action was denied by District Court of the United States for the Southern District of New York.  According to the Court, an intervention was permissible in an admiralty action only if the suit was in rem or the intervenor had an interest in proceeds in the registry of the court and in the present case, the admiralty action was in personam.  The appellate court ruled that the district judge exercised his discretion, and that the admiralty court had wide discretion as to the time of intervention. The court affirmed the denial of intervention by appellants for the reason that there was no abuse of discretion.