Lane meter: how a lane meter measures cargo space
On a roll-on, roll-off cargo ship, containers or other cargo can be rolled onto and off the decks. The lane meter measures the deck space in a strip: one lane wide and one meter long. The lane is defined as 2 meters wide, so the resulting area is 2 square meters, or 21.528 square feet. A length taken along that fixed-width strip therefore gives an area measurement. Its setting is the ship's deck, where the named lane adds the width that turns the meter-long stretch into a patch of space for rolled cargo.
A related practice appears in the moving industry, where a linear foot can mean a one-foot length of a moving van. That usually represents a volume of about 72 cubic feet, roughly two cubic meters. Outside that setting, linear foot describes a one-foot length of a long, narrow object, such as boards, pipes, or fencing sold by length. Linear meter and linear yard have similar uses. Like the lane meter, the moving-van measurement takes a length within a larger space. The van's use attaches a volume to the length, whereas the ship's fixed-width strip attaches deck area to it.
Cargo measurement has older names that joined a load to more than one kind of quantity. The last was an ancient northern European unit for large amounts, measured by mass, volume, or both. Its name is the German word for load, a meaning also preserved in the English word ballast. Generally, a last represented approximately 4000 pounds, about 1800 kilograms, as a mass unit. As volume, it was about 80 bushels or three cubic meters. Beside the lane meter's fixed strip of deck, the last belonged to a broader tradition in which a load could be expressed through weight or occupied volume.
In the United States, a last of wool formerly meant twelve sacks at 364 pounds per sack. The total was 4368 pounds, equivalent to 1981.3 kilograms. The sacks gave the load a counted form, while pounds expressed the amount in each sack and in the whole group. The cargo itself thus accompanied the measure's definition. The lane meter follows another route, naming deck area without defining the contents as a particular number of sacks. Wool's last retained a scale built around its own packaging and mass.
The Netherlands uses the last as a metric volume unit equal to exactly three cubic meters. In Germany, where it had previously been a volume of 2.819 cubic meters, it is also a metric mass unit equal to two metric tons, about 4409 pounds. The traditional name continued as metric values took their places within its uses. National setting accompanied the quantity: a Dutch last expressed volume, while the German term could express mass as well. These variations belong to the load measure's long life, linking an old word to modern metric quantities without making every use of the name represent the same dimension.
British timber measurement had a Riga last, equal to 80 cubic feet, or 2.265 cubic meters, of square-sawn timber. Forestry also used log as a distance unit of sixteen feet. That length matched the standard length of logs transported to the sawmill. Foresters developed techniques for estimating the height of a standing tree's marketable section in logs. Timber therefore appeared in measures of both volume and length, depending on what was being measured. A load of square-sawn wood could be expressed in Riga lasts, while the usable height of a tree could be estimated through the log-length unit before transport to a mill.
The simpler word load has remained a generally informal volume unit. In U.S. landscaping and some construction trades, it often means a cubic yard, equivalent to 0.764555 cubic meter. In ordinary U.S. usage, it can instead mean the volume of a pickup truck, a varying quantity. Britain sometimes used standardized loads before modern times, but their sizes depended on the commodity. A typical size was 40 bushels, roughly 1.4 cubic meters. The ordinary name for something carried could consequently refer to a specified volume, a truck's capacity, or a commodity-based amount, depending on the practical setting.
Travel had its own measure tied to an activity: the league was intended to represent roughly the distance a person could walk in an hour. It came from an ancient Celtic unit adopted by the Romans as the leuga and became common across western Europe. The early Celtic length seems to have been about 1.5 Roman miles, roughly 1.4 statute miles or 2275 meters. The unit grew longer over time, often reaching three miles in the locally used mile system. At sea, the league most often meant three nautical miles, exactly 5556 meters, carrying the traditional travel measure into a maritime distance.