Loading mark painted on the hull of merchant ships, first suggested by the 19th-century English politician Samuel Plimsoll. It shows the depth to which a vessel may be safely (and legally) loaded.
In 1872 he published a work entitled Our Seamen, which made a great impression throughout the country. Accordingly, on Plimsoll’s motion in 1873, a Royal Commission was appointed, and in 1875 a government bill was introduced, which Plimsoll, though regarding it as inadequate, resolved to accept.
On July 22, the Prime Minister, Benjamin Disraeli, announced that the bill would be dropped. Plimsoll lost his self-control, applied the term “villains” to members of the House, and shook his fist in the Speaker’s face.
Disraeli moved that he be reprimanded, but on the suggestion of Lord Hartington agreed to adjourn the matter for a week to allow Plimsoll time for reflection.
Eventually Plimsoll made an apology. The country, however, shared his view that the bill had been stifled by the pressure of the shipowners, and popular feeling forced the government to pass a bill which in the following year, was amended into the Merchant Shipping Act.
This gave stringent powers of inspection to the Board of Trade, and the mark that indicates the limit to which a ship may be loaded became generally known as Plimsoll’s mark or line.