Researchers have discovered that the builder of the Titanic struggled for years to obtain enough good rivets and riveters and ultimately settled on faulty materials that doomed the ship, which sank 96 years ago Tuesday.

The builder’s own archives, two scientists say, harbor evidence of a deadly mix of low quality rivets and lofty ambition as the builder labored to construct the three biggest ships in the world at once — the Titanic and two sisters, the Olympic and the Britannic.

For a decade, the scientists have argued that the storied liner went down fast after hitting an iceberg because the ship’s builder used substandard rivets that popped their heads and let tons of icy seawater rush in. More than 1,500 people died.

When the safety of the rivets was first questioned 10 years ago, the builder ignored the accusation and said it did not have an archivist who could address the issue.

Now, historians say new evidence uncovered in the archive of the builder, Harland and Wolff, in Belfast, Northern Ireland, settles the argument and finally solves the riddle of one of the most famous sinkings of all time. The company says the findings are deeply flawed.