This is a list of marine incidents I’ve studied or find interesting. Not all of them are significant in terms of their effect on the industry, but most of these have at least been discussed here.
The Blackwall (1867): Court case resulted in the “Blackwall Factors” (list of factors that help determine the size of a salvage award).
The Steamship Pennsylvania (1873): Resulted in the “Pennsylvania Rule” (a vessel that violates a rule designed to prevent collisions is assumed to be at fault in the event of an accident or casualty).
The Inchmaree (1885): Steamship explosion that resulted in the “Inchmaree Clause,” protecting against steam-power related losses.
SS Grandcamp (1947): Huge explosion while docked at port, caused by cargo of aluminum nitrate fertilizer (aka the Texas City Explosion). Led to new regulations that changed how volatile cargos can be stored and transported.
MS München (1972): Disappeared in rough North Sea weather. Most likely hit by a rogue wave.
Amoco Cadiz (1978): VLCC that ran aground off the coast of France, spilling thousands of tons of oil and causing environmental devastation. New laws governing salvage, marine pollution, and coastal navigation are just some of the wide-ranging effects of this disaster.
MV Summit Venture (1980): Bulk carrier that allided with the Sunshine Skyway Bridge due to the pilot navigating in low visibility weather. Part of the bridge collapsed and 35 people died.
MS Estonia (1994): Ferry sinking that killed ~850 people. Went down fast in the Baltic after taking on water in rough conditions. As noted by other people in this thread, this influenced the updated 1995 STCW.
MV Flare (1998): Bulk carrier that sank in the Gulf of St. Lawrence due to severe weather and a poorly maintained, old ship. It split apart and the stern sank in 30 minutes. The bow drifted for days before it finally sunk.
MV Rena (2011): Ran aground off the coast of New Zealand and split up. Resulting oil spill was a huge environmental disaster. (The wreck is now a thriving kelp forest!) Lack of adherence to navigational procedure, as well as fatigue and ineffective use of bridge equipment contributed.
Sincerity Ace (2019): Car carrier that caught fire in the Pacific Ocean. Crew abandoned ship with several casualties. The vessel was eventually abandoned and declared a loss.
Grande Costa d’Avorio (2023): Ro/ro container vessel fire in the Port of Newark that resulted in the deaths of two Newark firefighters. They were not equipped to handle the specific dangers and complexities of shipboard cargo hold fires, and lost their lives trying to fight it.