load line 
noun
Another term for Plimsoll line.The dignitaries at the Stuart presentation were told that she was the first warship in the world to carry a ‘load line’ on her hull....
- Elected to Parliament for Derby in 1868, he proposed a compulsory load line to prevent shipping accidents and obtained a royal commission on the subject in 1873.
- Checking regulations are not uniform, and can range from checking flags and safety radios to load lines showing how deep in the water a ship may sit without being overloaded.