Plimsoll Day

What the day is

Plimsoll Day is observed on February 10, the birthday of Samuel Plimsoll, born in Bristol in 1824. The mark on the side of every cargo ship carries his name.

Origin and background

The problem he attacked was deliberate. In the mid-nineteenth century British ships were routinely sent to sea dangerously overloaded, and some were barely seaworthy at all. Owners insured vessel and cargo, and a ship that sank paid out, so there were cases where losing the ship was more profitable than landing it. The crews had little choice: refusing to sail could mean prison for breach of contract, and thousands of sailors were dying each year. The vessels acquired a name, coffin ships.

Plimsoll, elected to Parliament in 1868, pursued it with a persistence that made him widely disliked in the chamber. He published a book naming the practice, was threatened with libel, and at one point was formally censured after losing his temper in the Commons and accusing members of being shipowners protecting their own interests. Public opinion moved decisively behind him, and the Merchant Shipping Act of 1876 made the load line compulsory.

The mark itself is simple and elegant. A circle crossed by a horizontal line shows the maximum safe loading depth, with additional lines for different water conditions, because water density varies. Warm fresh water is less dense than cold salt water, so a ship floats lower in it and may legally load less. Any inspector on any dock can read a ship's safety at a glance from shore.

The rubber-soled canvas shoe took the name because the band joining sole to upper resembles the mark, and water above it comes in.

How to take part

• Look up a photograph of a load line and learn to read the letters on it.
• Read about the coffin ships, which is the reason the regulation exists.
• Notice that the shoe is named after the ship marking, not the reverse.
• Consider how many safety rules look like red tape until you know the deaths behind them.