From Restitution: Fire and fury:
“Thomas Seymour plucked an iron cannonball from a crate containing dozens. “This one?” he asked.
Ned Founder, the ironworker, nodded vigorously as he replied, “A good choice, my lord.” He added hastily, “That looks like one of the better ones.” Wiping his soot-streaked hands on his leather apron, he avoided Thomas’ eyes.
“One of the better ones?” Thomas growled.
Ned sweated under the penetrating gaze of his paymaster. “Casting an iron ball with a hollow centre is not simple, my lord. Some are better; some are… less so. But we are improving. Making the hole a constant size is hard enough, but if it is off-centre, then the walls of the shell will not be a constant thickness…”
“And if the walls are not a constant thickness, what then?” Thomas pressed.
Ned’s shoulders slumped. “Variations mean unpredictable weaknesses…”
Thomas’ eyebrows shot up. “Unpredictable?” He barked out a short laugh devoid of humour. “So when I fire these at Spanish ships, some might work and some might not?”
“We’re getting better, my lord. Upon test-firing the last batch, maybe one in three…”
“One in three.” Thomas’ jaw clenched. Eighteen months. Many hundreds of pounds. Money he’d secretly siphoned from a variety of sources: the Bristol Mint, bribes from pirates, his late wife’s estate, funds that should have gone to his infant daughter.
All for ‘one in three’.”