The Birkenhead had arrived at the naval base in Simonstown, south of Cape Town, to load coal and allow some soldiers and many of the women and children to disembark.
The Birkenhead departed Simonstown on Feb. 25. The next morning, some 60 miles from the vessel's destination, it struck a submerged reef off Danger Point.
The ship immediately began to flood and sink. Men vainly tried manning the pumps while Seton ordered all other passengers on deck to prepare for evacuation.
Other soldiers were ordered to prepare the few lifeboats for launching.
All the women and children safely left the sinking ship in the first boat. A second boat loaded with survivors also departed.
Finally, the Birkenhead's captain released his crew, ordering them to go over the side and make for the boats. Seton realized that allowing the rest of those aboard to do the same would swamp the boats and endanger their passengers. He ordered his soldiers to hold their ranks and stand at attention — with only three breaking away.
The remaining 349 soldiers and nine officers went to the bottom with the Birkenhead, which sank only 25 minutes after hitting the reef.
"Every man did as he was directed. All received their orders, and had them carried out as if the men were embarking instead of going to the bottom; there was only this difference — that I never saw any embarkation conducted with so little noise or confusion," an eyewitness told the Times of London.
"Everyone did as he was directed and there was not a murmur or cry among them till the vessel made her final plunge," another survivor told The New York Times.
"And so they sank among the waves, carrying the habits of duty, which they had learnt as solders into that last act of self-sacrifice," observed The Times.
All women and children were saved, and since that time, the disaster has been credited with the tradition of "women and children first" when vessels need to be evacuated.