Maritime causes are those arising from maritime contracts, whether made at sea or on land, that is, such as relate to the commerce, business or navigation of the sea; as, charter parties, affreightments, marine loans, hypothecations, contracts for maritime service in building, repairing, supplying and navigating ships, contracts and quasi contracts respecting averages, contributions and jettisons; contracts relating to marine insurance, and those between owners of ships. 3 Bouv. Inst. n. 2621. 2. There are maritime causes also for torts and injuries committed at sea. 3. In general, the courts of admiralty have a concurrent jurisdiction with courts of law, of all maritime causes: and in some cases they have exclusive jurisdiction.