By design, Roman warships are not fundamentally different from the ships of Greece and the Hellenistic states of Asia Minor. Among the Romans, we find the same dozens and hundreds of oars as the main engine of the vessel, the same multi-tiered layout, approximately the same aesthetics of forgers and sterns.
All the same - but in a new round of evolution. Ships are getting bigger. They acquire artillery (lat.tormenta), a permanent party of marines (lat.manipularii or liburnarii), equipped with assault ramps, "ravens" and combat towers.
According to the Roman classification, all warships were called naves longae, "long ships", due to their relatively narrow hulls that withstand the proportion of width to the length of 1: 6 and more. The opposite of warships were transport (naves rotundae, "round ships").
Warships were divided on the basis of the presence / absence of a ram on naves rostrae (with a ram) and all the other, "just" ships. Also, since sometimes ships with one or even two rows of oars did not have a deck, there was a division into ships open, naves apertae (the Greeks had afracts), and ships closed, naves constratae (the Greeks had cataphracts).
Types
The main, most accurate and common classification is the division of ancient warships, depending on the number of rows of oars.
Ships with one row of oars (vertically) were called moners (moneris) or unirems, and in modern literature they are often called simply galleys,
with two - birems or liburns,
with three - trimers or trireme,
with four - tetrera or quadrireme,
with five - penters or quinquaries,
with six - hexers.
However, further a clear classification "smeared." In the antique literature one can find references to hepter / septer, oker, enner, decembering (ten-row?) And so on up to ceasefishing (sixteen-row ships!). Also known is the story of Athenaeus from Nawkratis about a tesseconconter ("forty-men"). If we understand by this the number of rowing tiers, then you get complete nonsense. Both in terms of technical and military.
The only imaginable semantic content of these names is the total number of rowers on one board, in one section (section) in all tiers. That is, for example, if we have one rower for one paddle in the bottom row, two in the next row, three in the third, and so on, then in total in five tiers we get 1 + 2 + 3 + 4 + 5 = 15 rowers . Such a ship, in principle, can be called kindetsimremoy.
In any case, the question of the architecture of the Roman (as well as the Carthaginian, Hellenistic, etc.) warships larger than the trireme is still open.
Roman ships were on average more similar in class to the Greek or Carthaginian. With a fair wind on the ship, masts were installed (up to three in quinkerems and hexers) and sails were raised on them. Large ships were sometimes armored with bronze plates and were almost always hung before the battle with oxen dipped in water to protect them from incendiary projectiles.
Also, on the eve of the collision with the enemy, the sails were rolled up and placed in the covers, and the masts were laid on the deck. The vast majority of Roman warships, in contrast, for example, from the Egyptian ones, did not have stationary, non-removable masts at all.
Roman ships, like the Greek, were optimized for coastal naval battles, and not for long-term raids on the high seas. It was impossible to provide a good habitability of an average ship for a hundred and fifty oarsmen, two or three dozen sailors and a centurion of marines. Therefore, in the evening the fleet sought to hit the shore. Crews, rowers and most of the marines left the ships and spent the night in tents. Morning sailed on.
Ships were built quickly. For 40-60 days, the Romans could build a quinqureme and put it into full operation. This explains the impressive size of the Roman fleets during the Punic Wars. For example, according to my calculations (cautious and therefore probably underestimated), during the First Punic War (264-241 BC) the Romans put into operation more than a thousand first-class warships: from trireme to quinquerama. (That is, not counting the uniri and birem.)
The ships had a relatively low seaworthiness and in the event of a strong sudden storm the fleet risked perishing almost at full strength. In particular, during the same First Punic War, the Romans lost at least 200 first class ships during storms and storms. On the other hand, due to sufficiently advanced technologies (and, it seems, not without the help of sophisticated Roman magicians), if the ship did not die from bad weather or in battle with the enemy, it served surprisingly long. 25-30 years were considered normal life. (For comparison: the English battleship Dreadnought (1906) was morally obsolete eight years after construction, and American aircraft carriers of the Essex type were brought into reserve through 10-15 years after the start of operation.)
Since sails sailed only with a fair wind, and the rest of the time they used exclusively the muscular strength of the rowers, the speed of the ships left much to be desired. Heavier Roman ships were even slower than the Greek. A ship capable of squeezing 7-8 knots (14 km / h) was considered "high-speed", and for quinquer the cruising speed in the 3-4 knot was considered quite decent.
The crew of the ship in the likeness of the Roman land army called the "centuria". There were two main officers on the ship: the captain (the "tri-hierarch"), responsible for the actual navigation and navigation, and the centurion responsible for the conduct of hostilities. The latter commanded several dozens of marines.
Contrary to popular belief, in the republican period (VI centuries. BC), all members of the crew of Roman ships, including rowers, were civilian. (The same, incidentally, applies to Greek the fleet.) Only during the Second Punic War (218-201 BC), as an extraordinary measure, the Romans went to the limited use of freedmen in the fleet. However, later, as rowers, they really began to increasingly use slaves and prisoners.
The fleet was commanded by initially two "naval duumvir" (duoviri navales). Subsequently, the fleet's prefects (praefecti), approximately equivalent in status to modern admirals, appeared. The ground commanders of the troops transported on the ships of the given compound sometimes disposed of separate formations from several to several dozen ships in a real combat situation.
Birems and Liburns
The birems were two-level rowboats, and the liburns could be built both in two- and single-deck versions. The usual number of rowers on the birem is 50-80, the number of marines is 30-50. In order to increase capacity, even small birems and liburns were often completed with a closed deck, which was not usually done on ships of a similar class in other fleets.

Fig. 1. Roman Birema (set artemon and main sail, the second row of oars removed)
Already during the First Punic War, it turned out that the Biremes could not effectively fight against the Carthaginian quadrireme with a high side, protected from a ram attack by a multitude of oars. To fight the Carthaginian ships, the Romans began to build quinquerme. Over the next centuries, the birems and liburns were used primarily for patrol, messenger and intelligence services, or for military operations in shallow water. Birems could also be effectively used against trade and combat single-row galleys (usually pirated), compared with which they were much better armed and protected.
However, during the Battle of Aktion (Akcium, 31 BC), it was Octavian’s lightweight biremes that were able to take over Antony’s large ships (triremes, quinquaries, and even desremors, according to some sources) due to their high maneuverability and, probably, wide use of incendiary projectiles.
Along with navigable libourians, the Romans built many different types of river liburn, which were used in combat operations and in patrolling the Rhine, Danube, and Nile. If we take into account that 20 of even not very large liburns are able to take on the full cohort of the Roman army (600 man), then it becomes clear that maneuverable liburn and birem formations were an ideal tactical means of rapid response in river, lagoon and skerry areas during operations against pirates, enemy foragers, and in disarray traveling through the water barriers of barbarian troops.

Fig. 2. Libourne-moner (top-back view)
Interesting details about the technology of manufacturing liburn can be found in Vegetia (IV, 32 and next).
Triremes
The standard trireme crew consisted of 150 rowers, 12 sailors, approximately 80 marines and a few officers. Transport capacity was if necessary 200-250 legionnaires.
The trireme was a faster ship compared to quadri and quinquer, and more powerful than birems and libours. In this case, the sizes of the trireme allowed, if necessary, to place on it throwing machines.
Trireme was a kind of "golden mean", a multifunctional cruiser of the ancient fleet. For this reason, the triremes were built in the hundreds and were the most common type of universal warship of the Mediterranean.

Fig. 3. Roman Trireme
Quadrireme
Quadriremos and larger warships were also not uncommon, but in large quantities they were built only directly during major military campaigns. Mostly, during the Punic, Syrian and Macedonian wars, i.e. in the III-II centuries. BC. Actually, the first quadri-and quinquermas were improved copies of the Carthaginian ships of similar classes, first encountered by the Romans during the First Punic War.

Fig. 4. Quadrireme
Quinquemaria
Such ships are called by ancient authors penters or quinquerms. In the old translations of the Roman texts you can also find the terms "five-finger" and "pyatirusnik".
These battleships of Antiquity were often not supplied with ram, and, being armed with throwing machines (up to 8 on board) and equipped with large quantities of marines (up to 300 people), served as a kind of floating fortresses with which the Carthaginians were very difficult to handle.
In a short time, the Romans put into operation 100 penter and 20 tririmes. And this is despite the fact that the Romans had no experience of building large ships before. At the beginning of the war, the Romans used trimers, which were kindly given to them by the Greek colonies in Italy (Tarent and others).
In Polybius we find: “The confirmation of what I just said about the extraordinary courage of the Romans can be the following: when they first conceived to ship their troops to Messen, they had not only sailing ships, but long ships in general and not even a single boat; fifty-five they took the ships and the three-deck from taratians and lokrov, as well as from the Eleyans and the inhabitants of Naples, and they were courageously transported troops.At this time, the Carthaginians attacked the Romans in the strait; shore and fell into the hands of the Romans, on the model of the Romans, and it built its entire fleet ... "

Fig. 5. Quinquerem
In total, during the First Punic War, the Romans built over 500 a quinqurem. During the same war, the first hexers were built (translated as "World stories"Polybia F.G. Mishchenko -" six-sided ").

It is also pertinent to mention a fundamentally different version of the quinquerema. Many historians point to the inconsistencies that arise when treating a quinquerma as a ship with five tiers placed one above another. In particular, the length and mass of the oysters of the uppermost row are critically large, and their effectiveness raises serious doubts. As an alternative construction, quinqueremes put forward a kind of “two-and-a-half-rem”, which has a chess arrangement of oars (see fig. 5-2). It is assumed that on each oar of the Quinquaries there were the rower 2-3, and not one, as, for example, on triremes.

Fig. 5-2. Quinquerem
Hexers
There is evidence that the Romans built more than five-tier ships. So, when in 117 AD Adrian’s legionnaires reached the Persian Gulf and the Red Sea; they built a fleet, the flagship of which was supposedly the hexer (see figure). However, already during the battle with the Carthaginian fleet under Eknome (First Punic War), the flagship ships of the Roman fleet were two hexers ("six-bows").
According to some calculations, the largest ship built using ancient technologies could be a seven-tiered ship up to 300 feet (approx. 90 m). A ship of greater length would inevitably break on the waves.

Fig. 6. Hexer, the super dreadnought of Antiquity
Super heavy ships
These include septers, enners and decimers. Both the first and second never were built massively. Antique historiography contains only a few meager references to these Leviathans. Obviously, the enners and decimers were very slow-moving and could not withstand the squadron speed on a par with the triremes and quinquaries. For this reason, they were used as battleships of coastal defense to protect their harbors, or to impose enemy naval fortresses as mobile platforms for siege towers, telescopic assault ladders (sambuka) and heavy artillery. In the linear battle, Mark Antony tried to use decimes (31 BC, the battle of Actium), but they were burned by the high-speed ships of Octavian Augustus.

Fig. 7. Enner, is a 3-4 longline combat ship, on each oar of which the rower's 2-3 sit. (weaponry - up to 12 throwing machines)

Fig. 8. Decrem (ca. 41 BC). It is a 2-3 longline combat ship, on each oar of which the rower 3-4 is seated. (weaponry - up to 12 throwing machines)
weaponry

Schematic drawing of boarding "crow"
The main weapons of the roman ship were marines:

If the Greeks and the Hellenistic states used mainly ramming as the main tactic, then the Romans, even during the First Punic War, relied on a decisive boarding battle. Roman manipularii (marines) had excellent fighting qualities. The Carthaginians, relying on the speed and maneuverability of their ships, had more skillful sailors, but could not oppose the similar soldiers to the Romans. First, they lost the naval battle at Milah, and a few years later, the Roman quinqurems, equipped with boarding "ravens", crushed the Carthaginian fleet at the Egata Islands.
Since the time of the First Punic War, the assault ramp- "raven" (lat.corvus) has become an almost indispensable attribute of Roman ships of the first class. The Crow was an assault ramp of special design, ten meters long and about 1,8 wide. It is named “raven” because of the characteristic klyuvoobrazny form of a large iron hook (see figure), located on the lower surface of the assault ramp. Either by ramming an enemy ship, or simply by breaking the oars in a sliding stroke, the Roman ship abruptly lowered the “raven”, which he pierced the deck with his steel hook and firmly stuck in it. The Roman Marines exposed their swords ... And after that, as the Roman authors usually say, "everything was determined by the personal prowess and zeal of the warriors who want to distinguish themselves in battle in front of their bosses."
Despite the skepticism of individual researchers, which contradicts not only common sense, but also primary sources, there is hardly any doubt about the use of throwing machines on ships of the Roman fleet.
For example, in Appian's “Civil Wars” (V, 119) we find: “When the appointed day came, with loud cries, the battle began with a race of rowers, throwing stones, incendiary projectiles, and arrows with their hands and hands. Then the ships themselves began to break each other, striking either sideways or epotides — bars extended in front, or to the bow where the blow was strongest and where he, dropping the crew, made the ship incapable of action.Some ships, sailing past, showered each other with shells and spears. " (my italics - A.Z.)
This and several other fragments of ancient authors allow us to conclude that the throwing machines, from the IV c. BC. widely spread in the land armies of the developed countries of Antiquity, they were also used on Hellenistic and Roman ships. At the same time, however, the question of the scale of the use of this fruit of the “high technologies” of Antiquity remains a matter of discussion.
In terms of their weight and dimensional characteristics and accuracy of firing, the most suitable for use on deck or half-deck ships of any class are seen light torsion two-shoulder gunners ("scorpions").

Scorpio, the most common artillery of the Roman fleet
Further, the use of such devices as harpaks (see below), as well as the firing of enemy ships and coastal fortifications with stone, lead and incendiary nuclei would have been impossible without the use of heavier double-shoulder torsion arrow-heads and stone-throwers - a ballist. Of course, the difficulties of aimed shooting from a swinging platform (which is any ship), considerable weight and dimensions limit the probable range of types of Roman ships on which a ballistae installation would be possible. However, on such types as, say, enners and descendants, which were precisely special floating artillery platforms, ballista is not so difficult to imagine.

Ballista
The latter also applies to onager, a single-arm torsion stone-thrower. There is every reason to believe that if onagry and used as a deck artillery, it is only for firing ground targets. Note that shown in Fig. 5 ship onager is equipped with wheels in the first place not in order to carry it from place to place. On the contrary, the onagres installed on the decks of the super-heavy Roman ships were probably fixed by ropes, although not tightly, but with certain tolerances, as in many cases the later gunpowder ship artillery. The wheels of the onager, as well as the wheels of the machines of the later medieval trebushy, served to compensate for the strong tipping moment that occurred at the moment of the shot.

Onager. The wheels on the deck of onagrov most likely served to compensate for the overturning moment that occurs at the time of the shot. Also pay attention to the hooks depicted in front of the machine. For them were supposed to wind up the ropes holding the onager in place during pitching.
The most interesting throwing machine, which could be used in the Roman fleet, should be considered polybol - semi-automatic shooter, which is an improved scorpion. If you believe the descriptions, this machine led continuous shooting arrows coming from the "store", located above the guide bed. The chain drive, which was driven by the rotation of the gate, at the same time cocked the polyball, pulling the string, gave an arrow from the “magazine” into the bed and, at the next turn, lowered the string. Thus, polybol can be recognized even as a fully automatic weapon with forced reload mechanics.

Polybol (semi-automatic arrow switch)
For fire support, the Romans also used mercenary Cretan archers who were famous for their marks and remarkable incendiary arrows ("malleoli").
In addition to arrows, spears, stones and iron-bound logs, Roman ship ballists also fired heavy iron harpaks (Latin harpax). The tip of the harpaksa had a clever design. After penetrating the body of the enemy ship, it was revealed, so it was almost impossible to remove the harpax back. Thus, the adversary "arkanili" preferably from two or three ships at once and proceeded to the favorite tactical method: in fact, a boarding battle.

Harpax Above - a harpaks, general view. At the bottom - the tip of the harpaksa, opened after breaking through the skin
Concerning the harpax, Appian reports the following: “Agrippa invented the so-called harpax - a five-foot log upholstered with iron and fitted at both ends with rings. On one of the rings hung a harpax, an iron hook, to the other was attached many small ropes, which were pulled with machines Garpaks, when he, being thrown by a catapult, hooked on an enemy ship.
But most of all, the harpax was different, dropping onto the ships due to its lightness from a long distance and hooking whenever the ropes forcefully pulled him back. Chopping it off for those who were attacked was difficult, since it was iron bound; the length made him ropes inaccessible in order to chop them off. Due to the fact that the gun was put into action for the first time, it was not yet invented such measures against him as sickles impaled on the poles. The only means that could come up against the harpaks, in view of the surprise of his appearance, is to move in the opposite direction, giving reverse. But since the opponents did the same, the rowers' forces were equal, the harpax continued to do its work. "[Civil wars", V, 118-119]
Despite all the described technical and artillery delights, the ram (Latin rostrum) was a much more reliable and powerful weapon of the ship than the ballistae and scorpions.
Rams were made of iron or bronze and, as a rule, were used in pairs. The large ram (rostrum itself) in the form of a high flat trident was under water and was intended to crush the underwater part of the enemy ship. Rostrum weighed very, very decently. For example, a bronze ram from a Greek Birema found by Israeli archeologists drew on 400 kg. It is easy to imagine how much the rostrum of the Roman ququinh weighed.
Small ram (proembolon) was above the water and had the form of a lamb, pork, crocodile head. This second, small, ram served as a buffer preventing (a) the destruction of the ship's stem when colliding with an enemy vessel; b) too deep penetration of the rostrum into the body of the enemy ship.
The latter could have dire consequences for the attacker. The ram could get stuck in the enemy corps and the attacker completely lost maneuverability. If the enemy ship was burning, it was possible to burn with him for the company. If the enemy ship was sinking, then at best it was possible to remain without a ram, and at worst - to drown with it.
A very exotic weapon was the so-called "dolphin". It was a large oblong stone or lead ingot, which was raised to the top of the mast or a special shot (that is, to a long turntable with a block and a winch) before the battle. When the enemy ship was in close proximity, the mast (shot) was filled up so that it was over the adversary, and the cable holding the "dolphin" was chopped off. A heavy disc fell down, breaking the deck, the rowers' benches and / or the bottom of the enemy ship.
It is believed, however, that the "dolphin" was effective only against open-ended ships, since only in this case could it break through the bottom and sink the enemy ship. In other words, the “dolphin” could be used against pirate felucci or liburn, but not in a collision with a first class ship. For this reason, the "dolphin" was rather an attribute of an unarmed merchant ship than a Roman triremes or quadrireme, already armed to the teeth.
Finally, various incendiary means were used on the Roman ships, which included the so-called. "braziers" and siphons.
The “braziers” were ordinary buckets, into which, just before the battle, they poured flammable liquid and set it on fire. Then the "brazier" was hung on the end of a long gaff or a shot. Thus, the "brazier" was carried out five to seven meters ahead along the ship's course, which allowed emptying a bucket of flammable liquid onto the deck of an enemy ship even before the proembolon and / or ram came into contact not only with the board, but even with the oars adversary.
It was with the help of the “braziers” that the Romans broke through the ranks of the Syrian fleet at the Battle of Panorm (190 BC).


Manual flamethrower (left) and flamethrower siphon (right)
Tactic
The tactics of the Roman fleet were simple and highly effective. Starting a rapprochement with the enemy fleet, the Romans bombarded him with a hail of incendiary arrows and other projectiles from throwing machines. Then, having come close, they sank the enemy's ships with ram attacks or fell into the boarding. Tactical art was to, energetically maneuvering, to attack one enemy ship with two or three of its own and thereby create an overwhelming numerical superiority in the boarding battle. When the enemy fired intense head-on fire from his throwing machines, the Roman marines were built by a turtle (as shown in the trireme picture on the previous page), waiting for a deadly hail.

The picture shows a Roman centurion storming the enemy fortifications in the structure of a turtle "
If the weather was favorable and there were "braziers" available - the Romans could try to burn the enemy ships without engaging in a boarding battle.
Based on: A. Zorich "Roman fleet. The design and types of ships"