Merchant Shipping Act 1876

The Act required owners of British sea-going cargo ships to mark a disc and load line on each side of the hull and made it an offence to load a ship so that the line was submerged. It strengthened Board of Trade powers to detain unsafe ships and made knowingly sending an unseaworthy ship to sea an offence. The Merchant Shipping Act 1890 let the Board of Trade, rather than owners, fix the mark. Load lines are now governed by the International Convention on Load Lines, 1966.

The load line is the original rule tying cargo weight to ship safety, the same principle behind today's container weight verification. Overloading endangers crews, cargo and other shippers' goods. For example, since July 2016 SOLAS has required a verified gross mass for every packed export container before loading, so a warehouse stuffing an export container must weigh it or calculate its weight by an approved method. Accurate weights prevent stack collapses and rolled bookings, extending the logic Plimsoll championed in 1876.

• Lloyd's Register1760 · Underwriters start grading the condition of ships

• First SOLAS Convention1914, never in force · First ship safety treaty, adopted after the Titanic
• International Convention for Safe Containers (CSC)1972, in force 1977 · Treaty requiring safety approval of shipping containers
• IMDG Code1965, mandatory since 2004 · IMO code for shipping dangerous goods by sea

1. Load line (watercraft), Wikipedia en.wikipedia.org