Purpose
The purpose of this page is to explain details of artillery and the rationale behind the Lords4 specific xbg unit and swivel guns.
Introduction
One of the most significant developments in warfare is the use of gunpowder as a propellant. Monarchs of the 1300s funded artillery experimentation lest they fall behind their warlike neighbors. It was the "arms race" of the Late Medieval.
This experimentation (investment in the Gunnery QR) led to the development throughout the 1300s of an enormous number of different-sized pieces, by a variety of manufacturing methods and designs. From this multitude several have been chosen as representative of certain classes.
NOTE: all units discussed require a Gunnery QR of at least 1, i.e. at least some working knowledge of gunpowder weapons.
Bombards
The light bombard (aka culverin) was mounted on a wooden frame, as shown below. On average they could fire "cannonballs" (stone balls hand-crafted by stonecutters) averaging 22 lbs (~10 kg) up to 1,800 yards. These could have devastating effect, their shot breaking limbs and pulping bodies as it bounced through a close-ordered enemy army. (Think big, fast, deadly bowling ball.) Additionally, a bombard's smoke and thunder were frightening (especially to horses) to an enemy unfamiliar with gunpowder weapons, giving a combat bonus.
Against the walls of fortresses and cities it was also effective, shattering the stone blocks and making entry breaches for an assault. Given the erratic quality of gunpowder, shot could likely overshoot the walls and smash houses and shops. More than one city surrendered at the sight of enemy artilery being deployed rather than endure bombardment.
In Lords4 culverins are represented by xbg ("light bombard gun") units, prerequisite being at least TL 7.
These pieces were also used aboard warships ("ordnance") against enemy ships as their shot was heavy enough to break hulls and masts. Shore bombardment was possible if the warship could get in close enough without running aground.
In Caravels (TL 7) several pieces were usually stored in the hold and raised by winches to the deck when needed. The larger carrack (TL 8) was built with gunports just above the water line to allow pieces to fire from lower decks. Carracks could carry more light bombards and as such have twice the combat value of caravels.
Both designs (hull storage and lower deck placement) were used to guard against the massive weight of ordnance making the ship top-heavy, each culverin weighing 2.5 to 3 tons. (The "center of gravity" concept was learned the hard way - more than one warship foundered on its maiden voyage.)
Development continued, making guns ever larger, and in the later 1300s/early 1400s basilisks were produced. On average they could fire "cannonballs" averaging 88 lbs (~40 kg) up to 700 yards. Their effects were similar to culverins but many times worse.
In the standard Lords UBC (Unit Build Chart) basilisks are represented by bg ("bombard gun") units, prerequisite being at least TL 8.
NOTE: weighing about 6 tons, basilisks were too heavy for use in caravels. Some carracks carried a pair of them, rather than a greater number of culverin.
Swivel Guns
The swivel gun was used on Renaissance-era ships, where they were mounted on side rails as shown below, serving as the main armament of cogs and transports against pirates. Warships had them also, but used their heavier ordnance first.
On average they could fire shot averaging 5 lbs (~2.5 kg) up to 500 yards, or be loaded with smaller stones (or anything else available) and used like giant shotguns.
There is no separate swivel gun unit. In Lords4, the presence of swivel guns on merchant shipping is represented by cogs having a combat stat of 0.1 and transports having a combat stat of 0.3, provided Gunnery QR is at least 1.