Were ships effective for sieging cities?

Question

When I play Civilization I find that ships can be quite strong for sieging cities, but a lot of cities aren't in range of the water. But in real life I know most major cities are near water sources. I'm wondering if ships played a big part in sieges in history and if they were actually practical for such a purpose?

Ships seem like mobile fortifications, which is nice, but also seem frightfully vulnerable to the likes of fire, cannonballs, etc. Perhaps there may have been a time period that allowed ships to shine?

Answer 1

Ships were definitely effective in siege warfare during the gunpowder age and the industrial age - effectively from the time when cannons became small enough to install in ships until the time they were made redundant by air power.

Despite being relatively fragile, ships were extremely concentrated artillery units. Fleets often outgunned the cities they were attacking - for example the British fleet that attacked New York in 1776 had many times more guns at its disposal than the city. A moving ship, while unarmoured, is also much harder to hit with a cannon than a static city.

Ships also had the advantage of manouverability. The British set a few ships upriver of New York to cut off supplies and reinforcements. They are also faster to move than most shore-based cannons, allowing the attackers to concentrate fireon a part of the defences without warning.

Shipboard artillery was used very effectively in World War 2 - for example at Normandy and in Italy as well as much of the Pacific. Combined with air support, but able to maintain station indefinitely, they destroyed fortifications and infrastructure and suppressed the movement of reinforcements. Battleships USS Wisconsin and USS Missouri provided gunnery support during the Gulf War, 1991. Arguably they remain useful today, although planes and missiles have replaced guns as the primary weapons of choice.

Answer 2

Yes, ships were effective in besieging cities, provided of course that the city was close to a waterline or a waterfront. You'll find below some examples of sieges of city that show advantages and difficulties when using ships against cities:

• Syracuse, 213 BC: during the siege of Syracuse by the Romans, it seems that the Romans have used their ships to attack the walls of the city, maybe using the corvus. This is controversial (corvus' existence is not even recognized by all historians), but if true this shows an usage. Also, Roman ships have faced catapults, maybe built on the advice of the famous Archimedes
• La Rochelle, 1628: Catholic fleet was used to blockade the city and to deter the English temptation to help the city with a fleet.
• Sebastopol, 1854: the Allied fleet (English, French, Turkish) tried to bomb the cities but was largely outgunned by the sheltered defense of the Russian city: the ships in woods faced earth-made fortifications and were repulsed.
• New Orleans, 1862: Unionists used heavily armed and protected ships, nearly ironclads for some of them, to attack the cities in the Mississppi, especially New Orleans.

Answer 3

In addition to the answers already posted, I'll add that sieging a city without ships might not be effective, because the city can be resupplied by sea.

Historical example:

The siege of Acre was the first significant counterattack by Guy of Jerusalem against Saladin, leader of the Muslims in Syria and Egypt. This pivotal siege formed part of what later became known as the Third Crusade. The siege lasted from August 1189 until July 1191, in which time the city's coastal position meant the attacking Latin force were unable to fully invest the city and Saladin was unable to fully relieve it with both sides receiving supplies and resources by sea. Finally, it was a key victory for the Crusaders and a serious setback for Saladin's ambition to destroy the Crusader states.

In other words, if the Crusaders had more ships they would have been able to full invest the city and likely take it sooner. Meanwhile, if Saladin had more ships, he would have been able to keep the city supplied and therefore successfully defend the city.