Tiller and Rudder orders were the complete opposite of one another: the command to turn "hard a-starboard," for example, meant to turn the wheel right under one system and left under the other.
As First Officer William Murdoch spotted the iceberg, his "hard a-starboard" order was wrongly interpreted by the Quartermaster Robert Hitchins, who was trained under the more archaic Tiller orders.
He turned the ship right instead of left, exactly toward the iceberg.
"The steersman panicked and the real reason why Titanic hit the iceberg, which has never come to light before, is because he turned the wheel the wrong way," said Patten.
Her grandfather Lightoller was not on watch at the time of the collision, but heard of the fatal mistake during the dramatic officer meeting which took place in the First Officer's cabin immediately after the collision.
During that meeting, Bruce Ismay, chairman of Titanic's owner, the White Star Line, persuaded the captain, Edward Smith, to keep sailing.
"Ismay insisted on keeping going, no doubt fearful of losing his investment and damaging his company's reputation," said Patten.
Continued sailing caused water to enter through the damaged hull, accelerating the sinking.
"The nearest ship was four hours away. Had she remained at 'Stop,' it's probable that Titanic would have floated until help arrived," Patten noted.
The only survivor who knew what had really happened, Lightoller covered up the blunder in two official inquiries.
According to Patten, he was worried that the truth would bankrupt the White Star Line's owners, thus making his colleagues jobless.
"The inquiry had to be a whitewash. The only person he told the full story to was his beloved wife, Sylvia, my grandmother," Patten said.
Claims around the Rudder/Tiller orders are not new to Titanic experts.
"In the Titanic world, it's always been one of those things that's referred to," Michael McCaughan, a maritime specialist and Titanic expert, told London's Guardian.
Meanwhile, Sally Neillson, the great granddaughter of Robert Hichins, who is also working on a Titanic book - "Hard A-Starboard" due to be published before the centenary anniversary of 2012 - totally rejected the claim.
"Hichins had 10 years experience, seven of those as a quartermaster. He sailed the Titanic for four days before the accident, during which he did shifts of four hours on, four hours off. He would have steered the vessel during these times, so been familiar with the systems," Neillson told UK TV Channel 4.
<Photo: Wikimedia Commons