The gaps, the longest of which measures about 39 feet (12 m) long, appear to have followed the line of the hull plates. This suggests that the iron rivets along the plate seams snapped off or popped open to create narrow gaps through which water flooded. ... ... Faults in the ship's hull may have been a contributing factor. Recovered pieces of
Titanic's hull plates appear to have shattered on impact with the iceberg without bending.
The plates in the central part of
Titanic's hull (covering approximately 60 per cent of the total) were held together with triple rows of
mild steel rivets, but the plates in the bow and stern were held together with double rows of
wrought iron rivets which may have been near their
stress limits even before the collision. These "Best" or No. 3 iron rivets had a high level of slag inclusions, making them more brittle than the more usual "Best-Best" No. 4 iron rivets, and more prone to snapping when put under stress, particularly in extreme cold.