Tabula in naufragio is a legal Latin phrase, literally interpreted as "a plank in a shipwreck".

The phrase is used in law

Law

Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...

 metaphorically to designate the power subsisting in a third (or subsequent) mortgagee, who took the third mortgage without notice of the second mortgage, and then acquired the first mortgage and attached it to the third mortgage, thereby obtaining priority over the second mortgagee.

According to Black's Law Dictionary

Black's Law Dictionary

Black's Law Dictionary is the most widely used law dictionary in the United States. It was founded by Henry Campbell Black. It is the reference of choice for definitions in legal briefs and court opinions and has been cited as a secondary legal authority in many U.S...

:

"It may be fairly said that the doctrine survives only in the unjust and much criticised English rule of tacking

Tacking (law)

Tacking is a legal concept arising under the common law relating to competing priorities between two or more security interests arising over the same asset. The concept is best illustrated by way of example....

."

The phrase was first attributed to Sir Matthew Hale

Matthew Hale (jurist)

Sir Matthew Hale SL was an influential English barrister, judge and jurist most noted for his treatise Historia Placitorum Coronæ, or The History of the Pleas of the Crown. Born to a barrister and his wife, who had both died by the time he was 5, Hale was raised by his father's relative, a strict...

, although Hale died over 200 years before the advent of the modern English doctrine of tacking.