maritime hypothecation for supplies

The vessel is not subject to a lien for a common debt of the master or owner. It is only under very special circumstances, and in an unforeseen and unexpected emergency, that an implied maritime hypothecation can be created… to make out a necessity within the admiralty rule, the supply must be really or apparently necessary at the time when it is furnished. But the more serious difficulty in the case, on the part of the libellant, is the entire absence of any proof, to show that there was also a necessity, at the time of procuring the supplies, for a credit upon the vessel. This proof is as essential as that of the necessity of the article itself.