An eighteen-ton wooden siege tower was a substantial mass. But it was still subject to Newton’s laws of motion.
At sunrise, Giles Croft stood inside the upper chamber of the north gate castle wall. The stone walls were three feet thick, built of dressed granite cut stone bonded with cured volcanic cement concrete. Through the narrow arrow embrasure, the southern road stretched away into the pine forest.
Giles unrolled a sheet of linen drafting paper across two flour barrels.
Captain Kenneth Drake stood beside him, resting both hands on his ten-foot iron-shod pacing rod. The veteran sapper looked tired, his eyes shadowed by long night watches.
“Warlord Bronn is three weeks out,” Kenneth said quietly. “Hollis reports their advance scouts are already cutting timber for corduroy roads across the outer bogs. If they bring thirty-foot towers within twenty yards of our timber wooden wall, they will drop boarding ramps right onto our heads. Our hunting bows can’t punch through their iron-faced mantlets.”
“Hunting bows operate on simple transverse wood bending,” Giles said. He tapped the drawing with his brass rule. “Their energy storage is constrained by human draw-weight and the elastic limit of yew. To destroy an eighteen-ton chassis at standoff range, we need clockwork energy storage.”
He pointed to the central assembly on the drafting linen.
“We need a heavy twisting force springald.”
Kenneth leaned over the drawing, his scarred brow furrowing as he studied the fine, detailed gearwork.
“This isn’t a royal giant crossbow,” Kenneth observed. “A giant crossbow has two outward-pointing bow arms that sweep back like a giant crossbow. It takes up fifteen feet of floor space and needs an open roof.”
“Exactly,” Giles said. “A traditional giant crossbow has a massive lateral footprint. It can’t operate inside an enclosed stone casemate without striking the stonework walls. A springald solves that spatial constraint by reversing the arm shape.”
He sketched the action with a piece of charcoal.
“The two bow arms swing inward, toward the centerline,” Giles explained. “The arms are driven not by bending wood, but by two upright twisting force skeins. Each skein is composed of two hundred tightly wound loops of drawn spring-steel wire and boiled ox sinew, held inside a heavy iron cage. When the arms are winched back, the skeins twist like tightened rope. Huge potential energy is stored in pure twisting shear.”
Kenneth’s fingers traced the narrow guide track. “And the arms snap forward inside the frame. The entire weapon is barely five feet wide.”
“Five feet wide and eight feet long,” Giles said. “It fits neatly behind an eight-inch upright stone embrasure. The crew is fully protected from enemy archers while running a heavy moving sniper platform.”
The first prototype, however, had nearly killed Master Borin Bronze-Lung.
Two days earlier, Giles and Caleb had assembled a trial test-bed in the timber yard using solid white oak bow arms and a carved hardwood ratchet pawl.
They had winched the arms back to three-quarter tension. The twisted sinew groaned, shaking with terrifying power.
Then, with an ear-splitting CRACK, the wooden ratchet pawl snapped clean off under seven thousand pounds of static tension.
The freed bowstring whipped across the bench like an iron cable. It snapped the left oak arm in half, sending three pounds of splintered timber whistling past Borin’s ear. The flying wood clipped the dwarf’s shoulder. It tore through his leather vest. Then it left a vicious, purple deep bruise across his collarbone.
Borin had spent twenty minutes swearing in three distinct dialects of dwarven mountain tongue, kicking the broken oak splinters into the sawdust.
“Wood has no stomach for sudden shear,” Giles had noted calmly, recording the failure in his ledger. “The sideways tearing force on the pawl exceeded four thousand pounds of pressure. We need cast glowing-bronze ratchets and layered composite arms.”
Master Borin climbed the castle wall ladder now, his left shoulder stiff from the bruise, carrying two heavy bronze ratchet wheels in his thick hands.
“Glowing-bronze ratchets,” Borin barked, setting them on the barrel. “Cast with twenty-four deep locking teeth. Tested them under a twelve-ton lever press. They won’t slip a notch even if a dragon pulls the cord.”
Behind Borin came Master Caleb Thorne-Wood, carrying two new curved timber arms.
“Layered white ash and hardened spring-steel,” Caleb said, setting the arms down for Giles’s check. “Four layers of seasoned ash glued with boiled hide glue, faced with two strips of quarter-inch spring steel from Borin’s forge, and bound in wet rawhide that shrank drum-tight as it dried. Stiff as church dogma.”
Giles took his feeler gauge and measured the laminations. “Zero delamination. Curve radius is within a tiny fraction of an inch of design specification. Caleb, begin assembling the carriage frames.”
For four days, the north castle wall was filled with the sounds of heavy joinery and metalwork.
The frame of the springald was built of ten-inch square white oak timbers, mortised and tenoned, heavy with heavy wrought-iron corner brackets.
In the forward corners sat the twin upright twisting force skeins.
Winding the skeins was a grueling, dangerous operation. Borin and six blacksmiths used long iron levers to wind the steel wire and ox sinew into tight, braided columns, applying sheep fat to prevent internal friction burns.
Every quarter-turn of the winding lever needed four men hauling on a block and tackle. With each rotation, the iron cages groaned under mounting thousands of foot-pounds of stored energy.
“Hold the dog!” Borin would roar, hammering an iron safety pin into the frame. “One slip and this skein will whip an arm off!”
Toby Karr watched from the doorway, his eyes wide as dinner plates. “It hums,” the boy whispered. “The wire hums like a hornet’s nest.”
“That’s elastic potential energy waiting for release,” Giles told him, adjusting the bronze ratchet pawl. “About twelve thousand foot-pounds of stored energy at full draw.”
By the fifth afternoon, the first springald was fully assembled in the north castle wall.
The weapon rested on a low timber carriage fitted with small bronze casters. That let the crew cross the entire rig fifteen degrees left or right. A heavy bronze screw beneath the rear transom provided fine upright height shift.
Borin brought up the ammunition.
It wasn’t a light war arrow. It was a six-foot bolt carved from straight-grained ash, two inches in width. At the rear were three copper fletchings, spiral-twisted to impart stabilizing spin in flight.
At the front was a heavy, chisel-pointed head of case-hardened steel, mounted in a discardable wooden sabot cup.
“Chisel point,” Borin said with fierce dwarven pride. “Heat-treated in salt water. It will bite into seasoned oak like a cold chisel through animal fat. Won’t glance off iron mantlets.”
Kenneth Drake stepped up to the weapon. He turned the bronze winding crank.
CLACK-CLACK.
The bronze pawls engaged the ratchet teeth with crisp, solid clicks. The heavy hemp bowstring drew back along the polished ash guide track. It pulled the two layered arms inward against the huge pushback of the twisted skeins.
The tension in the stone room became thick. The air smelled of hot animal fat, ozone, and stressed steel.
Kenneth laid a six-foot bolt into the bronze-lined track.
He looked along the sighting notch, aiming through the narrow arrow slit toward the southern road.
“The trigger is a bronze drop-sear,” Giles said. He pointed to a polished lever beside the stock. “Tripped by an iron lanyard cord. Kenneth, you may take the proof shot.”
Out on the southern road, two hundred yards away, Giles had set up a test target against the clay bank.
The target was a triple layer of seasoned oak planks, four inches thick, faced with a rusted iron breastplate salvaged from the broken raiders of the south ditch.
Kenneth took the lanyard in his hand. His knuckles were white.
“Fire,” Giles said quietly.
Kenneth pulled the lanyard.
THWIP-CRACK!
The release was not a roar like the Blunderbore cannon. It was a terrifying, whip-like snap that sounded like lightning splitting a green pine.
The twin layered arms slapped forward into the padded stops with a violent metal shudder.
Downrange, across two hundred yards of open air, a gray blur streaked through the sunlight.
The impact was instant.
A cloud of oak splinters and white dust erupted from the target.
The six-foot steel-tipped bolt struck the iron breastplate dead center. The chisel head punched through the plate as if it were parchment, bored through all four inches of seasoned oak, and buried itself three feet deep into the clay bank behind it.
The entire target assembly was knocked backward into the mud, shattered into kindling.
Kenneth Drake let out a long breath. He stared through the narrow embrasure at the smoking hole in the hillside, his jaw slack.
“By the Emperor’s throne,” Kenneth whispered. “Two hundred paces. Through plate and four inches of oak. A knight behind that mantlet would have been pinned to his cart before he heard the string snap.”
Borin Bronze-Lung burst into a booming, belly-shaking laugh, slapping the oak frame with both palms. “A sniper rifle built like a church pew! Look at that penetration! Take that, you tower-pushing scum!”
Giles stepped up to the breech with his fine measuring tongs, checking the bronze track for scoring or friction wear.
“Muzzle speed calculated at two hundred and forty feet per second,” Giles said in his standard calm tone. “Recoil absorption system operated within design envelope. The twisting force skeins kept ninety-eight percent of first tension.”
He turned to the second gatehouse castle wall across the raised stone road.
“Caleb, Borin. Begin assembly of Battery Two. We have forty-eight hours to complete the second weapon and calibrate our range tables.”
Giles took his brass sighting scope from its leather case and carried it to the low roof wall.
Down along the valley road, three prominent rock knolls rose from the peat scrub at regular intervals.
Giles sighted through the scope.
“Toby, take three red marker flags and three bags of lime,” Giles commanded. “We’re going to mark three stone cairns along the road: one hundred yards, two hundred yards, and three hundred yards.”
Toby scrambled down the ladder with the flags, shouting with excitement.
Giles adjusted the fine-scale screws on his sighting scope. He watched the boy run across the peat.
“Fine-tuning complete,” Giles muttered to himself, watching the white lime dust rise around Toby’s boots. “Once the range tables are engraved on brass, gunner error is removed. Now let’s see how their siege engines like basic projectiles.”