The "liquid fire" was hurled on to the ships of their enemies from siphons and burst into flames on contact. As it was reputed to be inextinguishable and burned even on water, it caused panic and dread.More on Greek Fire here.
In other cases, the idea was simple- send a ship, either already in flames or fused somehow to erupt into flames in short order, into the midst of an enemy fleet, particularly one at anchor or otherwise at a maneuvering disadvantage hoping that the "fire ship" would cause the target vessels to catch fire themselves. A variation on the theme was the use of explosives in the the fire ship -creating an "explosion ship." Wikipedia lists a number of examples of successful employment of fire ships, including
Francis Drake's attack on the Spanish Armada moored at Gravelines in 1588. The fire ships did no damage, but the Spanish scattered in panic and were easy prey for English ships.As might be guessed, the advent of metal hulled ships decreased the effectiveness of fire ships. However, the idea of using ships or boats as weapons to destroy enemy ships or shore facilities has not died out even to the present day.
First, of course, there is the idea of using a ship to ram an enemy vessel. While this was common tactic when ships were propelled by oars, as for example during the Battle of Salamis when the Greeks defeated the Persians, the tactic fell out of favor because, as noted here,
The ram was impractical on sailing ships, which were less maneuverable and encumbered by extensive masts and rigging, but steam propulsion brought it back into favor.So with the increase in the use of steam power during the American Civil War, the ram came back and stayed for awhile:
During the American Civil War, the Confederacy made extensive use of the ram, both on specialist ships and on ironclads that also carried heavy gun armament. Some conventional Union warships were modified for ramming and the North also employed a modest number of specialist rams in the Mississippi River area. These included the "Ellet Rams", which were Army ships that cooperated with the Navy, several rams captured from the Confederates, and two ships (Avenger and Vindicator) constructed for the Army but turned over to the Navy before completion in 1864.
Though subsequent events showed the ram to be a difficult weapon to use effectively and all too likely to harm friends more than foes, the incidents of the Civil War and the 1866 war between Austria and Italy kept it in favor beyond the end of the 19th Century. Though the ram was usually fitted as an auxiliary weapon on ships mainly armed with guns, the U.S. Navy did build one specialist ram ship in the 1890s,
USS Katahdin. During the two World Wars, the ram enjoyed a brief revival when many destroyers and other smaller warships were given specially hardened bows to attack surfaced submarines.
Royal Navy destroyer HMS Badger rammed a German U-boat during WWI(Badger photo from here). Indeed, the list of German submarine losses in WWI is full of U-boats sunk by being rammed. This continued in WWII, including the loss of U-576 by ramming by M/V Unicoi.
In addition to running other ships down, another option was explored by the British in World War II, in a raid on St. Nazaire also known as "Operation Chariot." The plan was to eliminate a safe haven to large German warships by destroying the drydock located at St. Nazaire, France:
St Nazaire was the only port along the French Atlantic coast that was capable of accommodating that sort of warship. The enormous Normandie Dock was, at that time, the largest dry dock in the world and was completed in April 1932 to hold the great passenger liner Normandie, and remained at the centre of the shipbuilding facilities that sprung up around the town prior to World War Two. If the Kriegsmarine were denied its use, it would be unlikely that they would risk the Tirpitz in the North Atlantic and instead use her to target the Arctic Convoy routes.The plan was to pack a destroyer (HMS Campbeltown ex USS Buchanan) with explosives and sail it up to the massive dry dock and explode it, then have a team of commandos conduct further operations to complete the elimination of the dry dock. After the ship rammed the dry dock, it sat there for a time, allowing the Germans to explore her, though they misunderstood her mission:
Naval troops and experts quickly examined her and decided that she was an obsolete ship that was expandable to the Royal Navy. They were slightly amused that they would try and ram the dock gates with a destroyer that, even with the concrete sections added to the front of the ship, would be too light to seriously damage the caisson by ramming. It never seemed to occur to them that there might be explosives aboard, or if it did, they did not seem to conduct a thorough enough search for them. With the naval staff satisfied the ship became a draw for a wide variety of German personnel and even locals. 09.00, the latest time she should have exploded came and went. By mid-morning literally hundreds of people were looking at Campeltown either from the shore or onboard her. Finally at 10.35 when the crowds had died down, the pencil fuses so carefully laid by Lt Tibbits, who was now dead, went off, detonating the four tons of explosives. The explosion was enormous, sending a shudder through the surrounding area. The ship was split in two, the front end being blown apart and the stern being lifted clear of the water. The caisson beneath her virtually disappeared and the remains of the ship were carried into the dry dock by the onrushing seawater. Around the town, windows were smashed, tiles came off roofs, and sheds were blown down. A number of German personnel who were onboard the Campbeltown when the explosives went off were blown to bits, those bits that were left being scattered far and wide. To the listening British survivors, the huge explosion brought them great elation - Operation Chariot had achieved its goal. Two days later the delayed-action torpedoes fired by Wynn went off, blowing up the outer lock gate to the submarine basin. All this heightened the sense of panic and paranoia in the Germans who were extremely twitchy for a long time afterwards. (Photo of Normandie dry dock complex from here)The Japanese also came up with a variation on the old "explosion ship" concept with deployment of their Shinyo:
... Japanese suicide boats developed during World War II. They were part of the wider Japanese Special Attack Units program.These one-man boats are described as:
These fast motorboats were driven by one man, to speeds of around 30 knots.Wikipedia credits the sinking of 9 U.S. ships to these boats and the crippling of another. See also here.
Around 6,200 Shinyo were produced for the Imperial Japanese Navy and 3,000 Maru-ni for the Imperial Japanese Army. Around 400 were transported to Okinawa and Formosa, and the rest were stored on the coast of Japan for the ultimate defense against the invasion of the Home islands.
U.S. Naval Armed Guards and Merchant Marine Mariners were attacked by suicide boats off Okinawa:
At less than two hours past midnight on the morning of May 4, the Paducah Victory was approached by a Japanese suicide boat which slipped alongside and then headed away at high speed as the Armed Guards fired.The U.S. Coast Guard also saw action against the suicide boats off Okinawa:
The Japanese also used small, fast boats, loaded with one or two depth charges to attack the fleet. The Japanese had hidden over 250 of these suicide boats around the island, but fortunately the Allied forces quickly captured the coastal areas and the Japanese were never able to use most of them.More on the Japanese suicide boats here. It should be noted that most of the Japanese boats were not designed for "one way" missions. Instead,
They were typically equipped with two depth charges as explosives or a bow mounted explosive charge. The ones equipped with depth charges were not actually suicide boats as the idea was to drop the depth charges and then turn around before the explosion. However, the wave from the explosion would probably have killed the crew, or at least have swamped the boat.As usual, what is impressive about all these ships is that man's efforts to destroy enemy forces so often use old ideas in new ways. Even today, the efforts of al Qaeda, the Tamil Sea Tigers and others using explosive laden boats (even as suicide weapons) are not inventing anything new, but simply putting old wine in new bottles.
There is very little new under the sun.
Which is a lesson to remember when thinking about maritime security.