Текст книги "Grantville Gazette 45"

Автор книги: Paula Goodlett

Соавторы: Kerryn Offord,Enrico Toro,Terry Howard,David Carrico,Griffin Barber,Rainer Prem,Caroline Palmer
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In canon, each of the USE ironclads is equipped with four 10"x 12 rifled muzzleloaders and six rifled 8" x 4 carronades. The ten-inchers fire studded shells. ( 1633Chap. 4; 1634: TBWChap. 38)

Smoothbores may be converted into rifles by insertion of a wrought iron tube (reducing the caliber, probably by about two inches) after reaming out the old bore to match the outer dimension of the tube.

With spherical shot, you impart spin by creating friction between the ball and barrel, either by stuffing a patch between the two, or giving the ball a coating of lead or other soft metal. The patch, typically cloth or leather, is placed on the mouth of the rifle and the ball is placed over it. The ball is then stuffed down. Besides promoting spin by filling the grooves, the patch helped prevent the ball from riding back upbore before firing, thus separating bullet and powder, and avoids transfer of lead from ball to barrel. (Fadala 94ff).

There will no doubt be heated arguments with regard to the fine points of rifling: the number of grooves, the degree of twist, and the shape of the groove.

Rifling does increase the friction between the projectile and the barrel, and this can reduce muzzle velocity and also generate heat and quicken the erosion of the barrel. This has led to proposal of hybrid guns, with either a smoothbore breech and a rifled muzzle (Alsop, US Patent 37193) or the reverse (A'Costa 4660312; Amspacker H1365). However, a more conventional solution to unacceptable friction has been to put the projectile into a plastic-sabot (see part 4) so that the friction is plastic-metal rather than metal-metal.

Gunmetal

Wrought iron. Until the sixteenth century, cannon were forged; the tubes were built up from longitudinal metal strips, and these were held together by metal hoops. (This was blacksmith work, and blacksmith Marthinus Ras made three muzzle loading 6.5 pounder cannon by this ancient method during the Boer War.)

The hooped bombard of the fourteenth century was made of wrought iron. But by mid-sixteenth century, the large wrought iron pieces were only found on small merchant ships and in peripheral fortifications. Small wrought iron swivel guns may still exist in our period.

Bronzefirst appeared in hooped bombards in the early-fifteenth century. In the sixteenth century, it was the dominant gun metal. I should note that the British navy has the incredibly annoying habit of identifying bronze guns as "brass." Brass is a copper-zinc alloy, bronze is copper-tin; in the sixteenth century, the preferred ratio was 90–10. (Guilmartin 307). While tough, bronze is soft and thus subject to abrasion, especially if the barrel is hot from repeated firing. Bronze also suffered from a lack of homogeneity. When cooling, the tin has a tendency to separate from the copper, causing white blotches called "tin spots" which are eaten away by the powder gas. (Ord1880,76ff).

There were essentially four kinds of bronze guns: pedreros, cannons, culverins and mortars. Pedreros are stone-throwers and because of the relatively low density of stone, they typically were of large caliber (12–50 pounders for sea service, up to 1000 pounders for land sieges), with short barrels (4–8 times caliber) and a reduced diameter (1/2 to 1/3 caliber) powder chamber. The Ottomans cast them muzzle down.

Both cannon and culverins fired cast iron cannonballs, but the culverins had long (18–40 times caliber, mostly 25+) unchambered bores, whereas the cannon had shorter (15–28 calibers, mostly 15–20) bores; early cannon often had reduced diameter powder chambers. (Guilmartin 175ff; Meide; Hoskins 119ff).

Mortars were designed to shoot at high angle trajectories, and were mostly used as siege weapons. A ship could carry mortars that could be landed and used to strike a position that was out of reach (because of shoals or batteries) of the ship's guns. Mortars had lengths of 1.5–3 calibers.

Cast ironis iron with more than 2 % carbon. Depending on how the carbon is combined, it may be called white (hard but brittle) or grey (softer but tougher, preferred for cannon). Cast iron guns appeared around 1543. Over the course of the seventeenth century, cast iron gradually supplanted bronze as cannon material. This was despite bronze's advantages; it didn't rust, it was easier to cast ("iron had a tendency to harden before all of it could be poured into the mould"-Lavery 84), it could be recast without loss of strength, and bronze cannon could always be made lighter than cast iron guns of equal strength. For example, in 1742, a British navy 32-9.5 weighed 6048 pounds in bronze and 6384 in cast iron, and a 42–10 was 7392 pounds in bronze and a walloping 8400 in iron. (Meide).

Nineteenth-century cast iron had a lower yield and breaking strength than bronze (Ord1800, 189), so additional metal was used, preferably at the breech. (Hazlett 82). While a more uniform cast iron could be made in the early-nineteenth century, thanks to improvements in iron-making (coke replacing charcoal, steam replacing water power)(Morriss 188-9), it remained unpredictably brittle (light field pieces were especially prone to bursting-Hazlett 220), thanks presumably to variations in the nonferrous constituents (phosphorus, sulfur, etc.). In the Civil War era, Rodman wrote, "we are at present far from possessing a praactical knowledge of the properties of cast iron in its application to gunfounding." (Wertime 164) and Cooke (53) made a similar complaint in 1880.

Unfortunately, bronze cannon were much more expensive-initially three– or four-fold; eight-fold by the 1670s (Unger 149; Lavery 84). This was the result of a decrease in the price of cast iron; bronze prices were stable. Consequently, bronze guns sometimes remained in service for more than a century-Rodger 215. (But even iron guns were very expensive and were kept in active service as long as possible-Glete 77.) Wrought iron reappeared as a reinforcing element in the mid-nineteenth century; in 1880 it was 2–3 times as expensive as cast iron. (Cooke 654).

As time passed, first the lighter guns were made from cast iron, then all guns save those on "prestige" ships (flagships and royal yachts) went ferrous. (Glete 24ff). The 42-pounder was first cast in iron in 1657, but 30 % of culverins were still bronze in 1660 (Nelson).

Even on first class warships, bronze was pretty much no longer on deck by the 1770s. (Although the British navy still had some bronze mortars in the 1860s.) Bronze continued to be used as a gun metal for field artillery in the nineteenth century, as late as the Crimean War and American Civil War, no doubt because of its weight advantage. These included a 14-pounder James rifle. Unfortunately, it wasn't suitable for rifled weapons. Since bronze is softer than iron, and the rifling exposed more in tin spots, "repeated firings rapidly wore down the lands, thus making the pieces increasingly inaccurate." (Kinard 193; Hazlett 52). Even for smoothbores, the softness and the tin spots were problematic when challenged by the heavier projectiles and more powerful charges of the nineteenth century.

In the 1870s, the Italians and French found that guns cast from phosphor bronze (stronger, more homogeneous metal) were superior to those made using ordinary bronze, but concluded that the advantage was too small; the phosphorus had to be added in exact proportions and was "unstable." So-called "bronze steel," an ordinary bronze cast under pressure while chilling the interior, and subsequently forged cold, was also considered, but eclipsed by steel. (Ord1880, 77, 187).

Cast steel. Steel is potentially superior to cast iron, and to wrought iron and bronze, but it is quite difficult to cast without hidden defects (Kinard 230). Krupp cast his first steel cannon in 1847 (Krause 59). There was only limited use of cast steel rifled cannon (3" Sawyer) in the ACW.

By the l890s, ordinary steel was replaced by nickel steel. (Krooth 89).

Cannon Manufacture

Hollow casting. In the early-seventeenth century, muzzle-loading iron cannon were cast as single hollow blocks. Making the mold was tricky. In essence, there were two clay molds, a hollow one for the exterior and a solid one (core) for the interior. (Hall, 11ff; Fisher).

The hollow mold was built up over a pattern made of wood, rope, clay and a friable material like horse dung; the pattern defined the desired shape of the cannon interior. The pattern was coated with a release material, such as an ash-fat mixture or a wax, so the actual mold material wouldn't stick. This mold material was also clay-based, and might be reinforced with rope or animal hair. The mold was reinforced with metal straps, the pattern was carefully removed from its interior, and the mold was baked. The core mold of course was simpler to make.

The complete mold was lowered into a pit, muzzle up. Note that the interior (core) mold had to be held centered inside the larger mold by a metal spacer ( cruzeta; chaplets), which would become part of the gun. In general, this didn't work out perfectly, the core would shift so the bore wouldn't be quite straight. (WeirML, 132).

The pit was filled with earth so as to hold the mold upright, a "feeding head" (riser) was attached, and the molten metal was poured into it. The latter had to have the right fluidity to properly fill the mold. Once the metal had cooled and solidified, the mold was broken so the casting could be removed. That meant that no two cannon could be identical.

The cannon was then finished off; the most important finishing steps were cutting off the riser, and reaming out the cast bore so that it had a smoother surface. Diego Prado y Tovar (1603) described a machine, possibly driven by animal power, for accomplishing this, However, the drilling was vertical, with the cannon suspended and slowly lowered over the drill. Note that the machine was merely finishing a hollow casting. Indeed, hollow casting is plainly described in Mieth, A New Description of Artillery(Frankfurt 1684); chapter V discusses the cruzeta (Rainer Prem transl.). Bores were cast to the diameter of the shot and drilled out to the added diameter of the windage. (Hoskins 43).

Clay molds are criticized in 1634: TBW, Chapter 38: "Clay had a very low porosity, which meant that air bubbles in the molten iron were often unable to escape when the guns were cast and, instead, formed dangerous cavities and weak points in the finished guns." The gun barrels of the USE ironclads used in the Baltic War were fabricated by sandcasting. "Sand was far more porous, which made for much stronger, tougher artillery pieces." Historically, sand molds were introduced in Britain about 1750. (Lavery 84).

Another problem was intrinsic to the vertical casting method; since the bottom (breech) was under greater pressure than the top, and also better insulated, it would have been the last to solidify, and therefore tin would have migrated downward. The muzzles were thus only 3–5 % tin, resulting in brittleness, which was compensated for by flaring the muzzle.(Guilmartin).

There were other modest improvements over the eighteenth century. In Britain, these included providing full-size drawings to the gun founders (1716) and using copper rather than wood cores.

We may deduce the improvement in tolerances by examining the weight variation of the pieces. "In 1665, guns from a single batch of 9ft demi-cannon varied from 44 to 62cwt, those of 8.5 feet from 43 to 47, and culverins of 10ft varied from 40 to 46 cwt." (83). In contrast, the 32-pounders surveyed in 1803 -6 were 55–57 cwt. (84).

Solid Casting. Over the period 1715 -45, Johann Maritz developed a new fabrication method. The cannon was cast solid, breech down, and then the bore was drilled out horizontally. The casting itself was much as in prior times, except that the core mold was no longer required. Boring itself, using an animal– or water-powered machine, took several days. (Kimpton). One curious aspect of the process is that it was the cannon that was rotated, the bit remaining stationary. (Alder 42). Solid casting was adopted in Britain in 1776 (Lavery 84).

Hot Blast. In the 1830s, American gunfounders attempted to cast iron by the more economical "hot blast" method, resulting in a disastrous loss of strength. At West Point foundry, 68.5 % of those cast by cold blast (1826–1834) were deemed "first class," compared to 4.02 % of those produced (1835 -39) by hot blast. (Hazlett 36, 42).

Rodman Guns. These were hollow cast, with a trick; the core was itself hollow, in fact, two concentric tubes, and was cooled with pumped water while the molten iron was poured in around it. The metal would thus cool inside out, pre-stressing it in a desirable way. (Wikipedia/Rodman_Gun).

Built-Up Construction. The 1855 Griffen "Ordnance Rifle," a 10-pounder cannon with a 3 inch rifled bore, was built up by welding wrought iron bands together around a mandrel, boring, and rifling. (Kinard 192), or by building up a mandrel with welded iron rods and then winding several bars in spiral fashion about it (Hazlett 121). Note its similarities to the ancient bombard, in that it was "built up" from wrought iron! However, it is important to note that instead of forging the iron with a hammer-as was done with the 1844 "Peacemaker," which burst and killed two cabinet members-Griffen forged his iron rods in a rolling mill.

There was also the British Armstrong gun. This went through several permutations. In one, wrought iron bars were twisted into spirals and welded on their edges to form the barrel. (Tennent 106). In some cases the twisted coils were themselves shrunk onto an inner tube of mild steel. (Morgan xvi).

Wrought iron's advantage was that it was four times stronger than cast iron, and thus able to help resist the higher internal stresses (the result of the reduced windage) of a rifled gun. Saving manufacturing cost and time, Parrott shrunk a wrought iron reinforcing hoop onto the breech of a rifled barrel cast in the usual way. However, "large Parrott rifles had the worst record of any Union cannon for premature bursting. Of 110 large caliber Union cannon that cracked or burst in action during the war, 83 were Parrotts. " After the first 1864 assault on Wilmington, Admiral Porter declared that the guns were "calculated to kill more of our men than those of the enemy." (Bell 8).

Around the end of the nineteenth century, the British and Japanese made use of wire wound construction. The "A" tube was wrapped multiple times with a high tensile strength wire and then the "B" tube was shrunk over this. (DiGiulian). The ten-inch guns of the new time line's USE Constitutionare "wire-wound" ( 1634: TBWChap. 38), presumably over a cast tube, but I don't know if a "B" tube was added.

In the early-twentieth century, heavy naval guns were built-up in hoop-over-tube fashion. The inner tube was placed breech end down in a cold pit, supported by a short mandrel. Heated hoops were placed one by one over the tube and cooled with a water spray, shrinking them onto the tube. (NAVORD. 136).

Spun Cast Monoblocs. In the 1920s, this was superseded by monobloc construction, made possible by the development of centrifugal spun casting. Despite the name, it typically involved concentric assembly of two or three tubes. Autofrettage was used to permanently deform the tubes in a desirable way. In autofrettage, the tube was pressurized hydraulically, just enough so that the outer limit was at its elastic limit, and then slowly relaxed. This increases the diameter of the bore and there is a permanent strain in the tube which varies from the inside diameter to the outside one.

It's likely that Grantville's machinists have heard of autofrettage. However, the autofrettage pressure must be much higher than the working pressure, which, for a cannon, is very high already. Autofrettage is typically used when pressures exceed 15,000 psi for brief periods of time, and so you must be able to achieve a higher pressure hydraulically.

Canon. In canon, the ironclad's main guns use Schedule 160 12" pipe as liners, wrapped with steel wire salvaged from the coal mine. ( 1633Chap. 4). That, of course, is heavily dependent on twentieth-century materials. Should steel wire become unavailable, the backup plan is to cast bronze reinforcements around the tubes. I imagine that if there were no steel tubes, they would use cast iron.

Quality Control

A newly-cast gun barrel might have cracks and cavities (Hoskins 42). Before a gun was accepted (and paid for) by the military, it was tested. The British proofed guns by loading them with a double charge, and setting it off. The gun was then examined for cracks; this included filling it with water to see if it leaked. (Lavery 84). The gun would also be examined, usually visually, for the correctness of the bore diameter and the trueness of the bore. Note that if the bore droops, or bows to the side, this will impede the escape of the ball, and thus increase the pressure that the barrel must withstand (Hoskins 65).

Flaws may develop (or worsen) as a result of use (or misuse). Firing the gun too rapidly so that it overheats, overcharging the gun, and ramming the gun too hard all can create problems. Bronze has the great advantage that it tends to "crack and bulge before it bursts," unlike iron. (Id.).

Now let's discuss the Gribeauval system, which gave the French the best artillery in late-eighteenth-century Europe. Much attention was given to tightening the manufacturing tolerances for both the bore and for the cannon balls it fired. Rather than merely judge by eye whether the bore was dimensionally correct, the Gribeauvalist inspectors used a caliper gauge to measure the diameter to within 0.025 mm. (Alder 150).

In canon, Grantville's machine shops quickly demonstrated that they could do even better. Early in the new time line, Ollie Reardon manufactures new three-pounder cannon for Gustav Adolf. The metal is soft bronze, in which he drills out the bore on a lathe. He notes that ideally the finish cut would be with a reamer. (Flint, 1632, chapter 46). Whether reamed or not, the final product impresses Torstensson, Gustav's Chief of Artillery: "Those bores are perfectly identical!" In response, Rebecca shows him a micrometer, and explains that it has an accuracy of 1/1000th of an inch (one mil). (chapter 47).

Gun Popularity

Table 1–3 shows that even in Elizabethan times, there was a trend toward heavier armament:

I don't have a bronze vs. iron breakdown for 1585, but in 1592, naval guns were 79 % bronze. (Walton 220). Thus, there was also a trend toward replacing bronze with cast iron.

This information is still relevant as of RoF; both ships and guns typically remained in service for several decades. The British warships in active service in 1631 included the British Bear(40 guns, 1580), Adventure(26 guns, 1594), Warspite(32, 1596), Nonsuch(32, 1605), and Assurance(34, 1605). As for guns, on the Portuguese Santissimo Sacramento(launched probably in 1653; sunk 1668), the bronze guns are dated, either explicitly by the caster, or implicitly by design. Nine were cast before 1600. Eleven, between 1600 and 1650. Five were just identified as mid-1600s, and one was 1653. (Guilmartin). On the Kronan(sank 1676), one gun was cast in 1514 (Hoskins 18).

It would of course be nice to have comprehensive data for a date closer to the RoF (1631). I have found the Royal Ordinance Inventory for 1637 (Collins), but that's for the army. While the Royal Ordinance also supplied the navy, the latter would have requisitioned a different assortment.

What I can provide is data for individual ships; table 1–4 attempts to correct the usual British bias by providing some French, Danish, Swedish and Dutch examples.

By way of comparison, the principal Napoleonic battleship, the "74", usually had 28x32pdr, 28x18pdr, 18x9pdr. (Lavery 121).

In the table, I introduce the metric "broadside weight," the total weight of shot that can be fired at one time. This is probably a better measure of the power of a warship than just the nominal number of guns.

From a ship design standpoint, another important metric is the ratio of that broadside weight (pounds) to the ship displacement (tonnes); for the Swedish navy, it was around 0.4 in the 1630s, but increased to 0.75 in 1671. (Glete 571). In that year, the Kronancarried an armament of about 180 tonnes, 8 % of its 2,300 tonne displacement. (572).

Horizontal Distribution of Guns

We may recognize three basic gun arrangements: predominantly frontal; predominantly broadside; and turreted. The Mediterranean galleys are in the first category. One of the more powerful of the Venetian galleys at Lepanto (1571) might have a 52–55 pound full cannon, flanked by an inner pair of 12-pounders and an outer pair of 6-pounders. And it could have a second deck, carrying swivel guns, as was certainly the case for the larger Spanish galleys. (Guilmartin, 322-3). In the eighteenth and nineteenth centuries one could also find heavy frontal armament in certain specialized warships, bomb ketches and rocket ships. In the twentieth century, we have a similar arrangement on torpedo boats and missile boats. And attack submarines may be said to have a spinal armament, firing torpedoes from bow or stern.

Most warships of the late-sixteenth through mid-nineteenth centuries were designed to deliver powerful broadsides, but had rather weak bow and stern armament. Once the "line ahead" formation and related tactics, which lent themselves to delivering broadsides, were developed in the mid-seventeenth century, this was particularly true of capital ships. A frigate or lesser vessel was more likely to have chase guns.

Despite the importance of the broadside, seventeenth-century French warships tended to have relatively powerful bow and stern armament, because they were used in the Mediterranean against galleys. This required some adjustment in the hull to provide a good firing arc. (Langstrom 167). In general, since the number of bow and stern guns was limited by space, those tended to be the ones with the best range and accuracy. (ChapelleHASN 12).

It's perhaps worth noting that warship designers of the second half of the nineteenth century were "ram-crazy"; this in turn led to an undue emphasis on frontal firepower for steam-powered ironclads.

For a ship with broadside armament, the length determines how many guns it can carry per deck. Length was limited by structural concerns; local inequalities of weight and buoyancy would cause it to droop in the center (hogging) or sometimes at the ends (sagging). These in turn imposed strains on the hull; they were proportional to the square of the length. Wooden-hulled warships consequently weren't much longer than 200 feet; a British first rate of the 1745 Establishment was 179 feet at the gun deck. (Ireland 41).

Of course, the number of guns carried on a deck of particular length depended on the spacing between the gunports, and how close they came to the bow or stern. On the Dauphin Royal(1735), 74 guns, there were 13 ports to a side, the foremost about 18 feet from the stem and the aftmost about 10 feet from the stern. The port width was 2'10" and the distance between ports (edge-edge) was 7'7". (du Monceau 4).

Gunport spacing was limited by the area and crew needed to work the guns; the more powerful the gun, the greater these were. Gunport breadth, for example, was 3 feet for a 48-pdr and 1.5 for at 4-pdr (Id). The spacing was also affected by the framing; you didn't want to cut through a frame and weaken the hull. A mid-seventeenth-century Dutch admiralty had these rules of thumb: gunport spacing (center-center) 20 shot diameters; height, six diameters; width, five (Hoving 104). A mid-eighteenth-century rule allows for 25 shot diameter spacing and 6.5 diameter width, with the sill 3.5 diameters above the deck (Davis1984,110).

In the British 1745 establishment, no warship had more than 28 guns on a single full deck. However, there were post-establishment British warships, such as the First Rate Victory(1765) and the "Large" class 74s, with 30 guns on the lowest gun deck (Lavery 121ff). And in 1764, du Monceau, said that a 112-gun French warship had 32 guns (24-pdr) on its second deck.

If you wanted more guns than a single full deck could accommodate, you put them on the quarterdeck or forecastle, or, if that still wasn't enough, you added a second (or if need be a third) full deck.

The mid-nineteenth-century introduction of iron and steel construction allowed warships to be lengthened, and thus history has some examples of some long "broadside ironclads." The longest of these was the HMS Minotaur(1863), 407 feet long, a sail/steam hybrid. There were also two-decker broadside ironclads, such as the French Magenta(1862), 282 feet long. (Neilson).

Broadside guns had a limited firing arc. In Napoleonic warships, the range of traversal was 40–45 degrees before or abaft the beam; this was apparently an improvement on earlier warships (O'Neill 71). However, in steam ironclads like HMS Warrior, the gunports were narrowed, thereby reducing the arc of fire (Lambert 46). The theory was that with steam propulsion, they weren't subject to the vagaries of the wind, and therefore could maneuver as needed to bring the guns to bear. Moreover, firing at extreme angles reduced the rate of fire. I also figure that the narrower gunports meant that the guns were less vulnerable to counterfire.

I believe the first turret ship was the wooden Royal Sovereign(1857); Eriksson's ironclad USS Monitor(1862) was the first to engage in battle. The advantage of the turret was that by rotation it could bring its gun(s) to bear in any direction, save for those obstructed by the ship's superstructure (including funnels, masts, and other turrets). Because of the size and expense of the turret, the tendency was for turreted warships to be fitted with a small number of very powerful guns. For this discussion "turreted" may mean a true turret (armor rotates) or a barbette (armor stationary).

Sails, masts, spars and stays would of course restrict the firing arcs; nonetheless, many early turreted warships were hybrids (sail/steam) because of doubts as to the reliability of the engine.

This led to a variety of curious expedients. On the ill-fated HMS Captain(1869), the two turrets were on the lower (main) deck, and the masts were stayed to the upper (hurricane) deck. I would imagine that this arrangement would limit how high the guns could be elevated. The hurricane deck was dispensed with on the double-turreted HMS Wyvernand HMS Scorpion(1863), on which the turrets flanked the main mast. Captain Coles proposed use of iron shrouds and stays. (Breyer 34).

HMS Devastation(1871) was the first turreted warship without rigging (it had a central mast for signaling and observation). HMS Inflexible(1876) had two screws driven by compound steam engines, and two masts that could carry 18,500 sf sail (Wikipedia). The latter was removed in 1885. (Breyer). While I am not aware of later turreted warships with sails, the broadside-armed HMS Calypso(1883) was ship-rigged (Ireland1997, 36) and the Russian cruiser Rurik(1892), barque-rigged.

Early turreted warships included those with one ( USS Monitor), two ( USS Onondaga) and even three ( USS Roanoke) turrets. With multiple turret designs, one has the concern of where to place the turrets. The most obvious arrangement was to place them single file on the centerline. The obvious problem was that a bow turret couldn't fire directly astern, and a central turret (as on the HMS Monarch(1868)) couldn't safely shoot fore or aft.

One alternative was to mount the extra turrets on the side (wings). This increased the frontal fire at the expense of broadside fire. In theory, wing turrets could be staggered, and fire if need be across the deck. but that tended not to be too good for the deck. And the centerline design was structurally sounder.

Another option was to stack the turrets, like the tiers on a wedding cake. On USS Kearsarge(1898), the double-decker turrets turned as a unit. It's reported that the vibration of the 13" guns below interfered with the firing of the 8" guns above. (cityofart.net)

The 1870s Italian navy experimented with a "diagonal reduit", in which two turrets were mounted near the center of the ship but diagonally offset from it. (Breyer 33).

A single turret could carry one, two or even three guns, but if it attempted to fire multiple guns simultaneously, "invariably, one of the guns was thrown off target by the firing of the first weapon." (Kaufmann 5).

With muzzle loaders, the turrets had to be of large diameter, but the guns short-barreled, so they could be run back and reloaded inside. (Ireland1997, 38).

The mechanisms of turret gun laying and loading are discussed in part 2, and the armoring of turrets in part 5.

Vertical Arrangement of Guns

Positioning the gun on a higher deck has the advantage that the gunports are less likely to be forced to close as a result of rough sea conditions (Laing 76). Raleigh urged that the ship be designed and laden so that the lowest tier of ordnance was four feet above the water (Creuze 17). An upper deck gun will also have increased range (as predicted by Torricelli) and can take advantage of plunging fire (shooting at the flimsy enemy deck, not the relatively stout side). However, if the enemy is close at hand, the gun might not be able to depress enough to fire upon it, and the higher the guns are, the higher the ship's center of gravity must be, reducing its initial lateral stability (but the higher freeboard does provide some compensation by increasing the angle of vanishing stability).

In the fifteenth century, ships had guns mounted high up, in the aptly named forecastles and sterncastles. The size and number of these guns was limited by their effect on stability. In the early-sixteenth century, gundecks and gunports were introduced. Since the armament was lower, it could be made heavier. (Svensson 16). As broadsides became more effective, the superstructures became less useful and were reduced in size. The early-seventeenth century was a transitional stage in which the capital ships mounted heavy broadside armaments, but still had significant superstructures.