The lengthening of a crack formed in the shell plating of a ship may be prevented by __________.

Correct Answer: Option A — drilling a hole at each end of the crack

Drilling a hole at the terminus of a crack, known as 'stop-drilling,' effectively redistributes the stress concentration away from the sharp crack tip. This prevents further propagation of the fracture through the shell plating, providing a temporary mechanical solution to maintain hull integrity until permanent welding repairs are completed.