There are several myths that surface when talking about Roman naval history. Most of these come to light whenever I put on an ancients Roman naval miniatures game and they should be dispelled. The below list are the most common misconceptions about Roman naval history:
Myth Number 1: The Romans used slaves to row their ships.
Neither the Romans nor the Greeks employed slaves as rowers onboard military vessels that were expecting to go into combat. There is some speculation that slaves may have been used to move a military vessel from one port to another in times of peace, but never in combat. Slaves had neither the training, the skill, nor the motivation required to row warships and could not be trusted to act in the best interests of those who owned or controlled the ships, especially in combat when the slaves may have been set free by those who captured their ship. Freeman were used to man the oars of warships, and in most cases, these were trained individuals who were well paid in their days. Paid freemen are more likely to perform at their best.
It is true that rowers may not have been involved in as many fights their ship marines, but when push came to shove, rowers could and did fight along side their ship's marine. Some historians insist that short swords were kept on board galleys for use by the rowers when boarding actions were being fought. Remember: The losers of naval battles often ended up as the slaves of the winners. A rower is a freeman who probably did not want to end up as a slave for the rest of his life in some far away foreign place.
Myth Number 3: Catapults could not be used onboard ships because their recoil was too severe for the ship to withstand.
The Romans, beginning around 80 B.C., started to place a lot more emphasis on placing artillery onboard their war galleys, although there was always a preference for the placement and use of marines to fight the hand-to-hand actions. The Romans used ballistae catapults onboard their warships, and these catapults have no recoil and therefore were ideal for placement onboard galleys. During Julius Caesar's reign, artillery moved more to the forefront as a main offensive arm of the Roman navy. Often with the spoils of war, after a successful military campaign, the Roman navy ended up with many of the enemy's catapults. Light and medium ballistae were used regularly on Roman warships, whereas heavy ballistae were probably not used due to the weight of the weapon and also because of the excessive weight of its ammunition.
Myth Number 4: Artillery fired projectiles with a high arch and was relatively ineffective
Ballistae catapults fired virtually flat trajectory up to at least 200 meters (some ancient historians stated that the range could go as high as 400 meters) and was deadly. A light ballistae could penetrate 4 inches of wood planking, whereas a medium ballistae fired a 10lb concrete/marble ball projectile that could far surpass the light ballistae for penetrating power (if you think cannon ball, you are on the right track). Rowing crews in a cataphract ship, being hit at short range by a medium ballistae were probably injured in high numbers by these 10lb projectiles. Being in a cataphract ship was not a guarantee of protection against artillery.
Myth Number 5: Ramming was a highly effect means of attacking and sinking enemy ships
Ramming, by the end of Alexander the Great's time, was a risky and unsure system of attack that required great skill, and a fair amount of luck, to be pulled off successfully. One miscalculation could mean that you would inflict more damage on your own ship than onto the ship you attempted to ram. More ships of this period were starting to be built with reinforced waterlines which meant that ramming attacks were becoming less effective. To sink an enemy ship by ramming often meant having to ram the target more than once before it would finally sink. The Rhodians partly solved this problem by having their rams mounted lower on their ship's bows allowing them to strike an enemy ship's hull beneath the reinforced waterline belt, but the trade off was that has the ship's bow could drag when attempting to beach the ship, as well as other problems (perhaps decreasing the ships draft?). The Romans circumvented ramming altogether by using boarding as their main method of attack. Boarding combat was a easier to control, quicker to resolve and safer than ramming, and the Romans had a ready stock of heavily armed, trained soldiers from their land armies. This was an easy solution for the Romans as well as also being a highly effective one since most other navies only used lightly armed and armoured marines.
Myth Number 6: Romans always preferred using Corvus (Raven) which was a ramp like device that was placed in the bow of their larger Quinquereme ships -- the ramps was dropped onto to an opponent's ship deck allowing the Roman marines to storm across for close quarter combat.
The Romans only used Corvus during the First Punic War (264BC to 241BC), and then only for about 5 years from its introduction in 264 BC. From around 269 BC, it was never used again. Corvus works very well, but it is also a very heavy device that could not be easily jettisoned once it has been mounted onto a warship. Corvus made the Roman warships slow and sluggish, but, more important, also top heavy. This proved a disaster for a Roman fleet that were caught out at sea during a violent storm. Their top heavy ships sank easily and in great numbers. This disaster happened twice within a three year period and in both cases, more 80% of their ships sank, totaling as many as 100,000 casualties. With such a bitter lesson learned, the Romans discontinues the use of Corvus (and rightly so).
Myth Number 7: Before the First Punic War (264BC to 241BC), Rome did not posses a navy.
Before the First Punic War (264BC to 241BC), the Romans did not build their own warships and did not possess a large navy, but they did, for at least 50 years prior, posses a navy. Their navy was thought to be composed of ships no larger than Triremes and numbering fewer than 50 ships. This small force was used for the purpose of escorting grain ships.
Myth Number 8: The Roman navy played only a small part in land campaigns and was therefore insignificant.
It could be argued that without a navy, many Roman land battles could never have been fought and won. The Roman navy fought far too many battles, in virtually every Roman campaign, than can be counted. The navy's conflicts were often small actions, numbering fewer than 30 ships aside, but they were numerous and usually not recorded by the historians. The battles and skirmishes recorded show a long history of fighting that would embarrass the average Roman land commander with their frequency. Often when historians noted that a Roman army sat idle in campaign for the better part of six months, they failed to record that the Roman navy was fighting very fierce and bloody naval battles trying desperately to keep the supply lines open to their idle land army. The Roman navy were the unsung heroes of the Roman Empire.
Myth Number 9: The main idea of naval combat was to sink your opponent.
Capturing enemy ships was preferable to the sinking of enemy ships. It is easier and cheaper to refit a captured warship than it is to build a new one from scratch. Also, nothing hurts an enemy more than seeing one of their warships serving in the navy of their former enemy. Sinking of war galleys was, for the most part, impossible since galleys were built "light" so as to attain good speeds and maneuverability. A ship that is recorded as having sunk during a battle, in fact really just sinks up to its deck, and then floats around as a wreck for the next few weeks, or even, perhaps, the next few months before finally sinking or breaking up. It has been rumoured that even sunken/floating wrecks were salvaged by whomever found and recovered the wreck. It has been theorized that the only time a warship actually sank in battle was when it was constructed from green wood, which is heavier than the usual dried wood