Naval strike drones: from ancient brigands to modern times

Recently, our colleagues from Defense Express published an interesting article about the predecessor of modern maritime strike drones, the remotely operated Fernlenkboot, which was developed and tested by the German Imperial Navy during World War I. Without detracting from the achievements of the German arms manufacturers, for this was indeed the first almost modern naval drone in terms of design, I would like to mention other predecessors of the offensive naval UAV. For this history began much earlier, about 1800 years ago.

Firewalls

The idea of creating brander (German: brander, from branden – to burn), special vessels loaded with combustible and/or explosive substances and intended to burn enemy ships, was on the surface. In the era of sailing and rowing fleets, sun-dried, tarred wooden ships burned very well, even without the help of Greek fire or the semi-mythical mirrors of Archimedes. And a fire at sea is the worst thing that can happen to a ship.

You load an old ship that is no longer capable of anything with flammable substances (brushwood, reeds, tar, grease, etc.) and send it downstream or downwind toward the enemy. Of course, it is better to have a minimal crew steer the ship for most of the way, then leave the ship in boats or jump overboard, even better to do it at night or in fog, of course setting fire to the brushwood at the last moment. Branders worked well against enemy ships on raids or in narrow straits, but they were almost useless on the open sea. But even if the brander did not set fire to the enemy ship, it forced it to maneuver, break formation, and introduce an element of panic that could tip the scales in the other direction during a battle.

The first documented successful use of brigands occurred during the Battle of Red Rock in the winter of 208/209 AD. This is one of the most famous battles in Chinese history, in which the Eastern Wu forces under Zhou Yu fought against the forces of the Han chancellor Cao Cao. The defeat in this battle led to the fall of the Han Dynasty and the beginning of the Sangguo or Three States Period.

Cao Cao, who had a significant numerical advantage (800,000 to 50,000 according to some sources, 240,000 to 50,000 according to others), for some reason decided to tie his ships together, ostensibly to reduce rocking, because his army had too many soldiers from northern China who could not tolerate waves. It was a perfect target for the brigands – large and stationary. The fleet caught fire, many were burned or drowned, panic ensued, and an attack by Zhou Yu’s troops on shore completed the defeat.

The next known use of branders took place in 468 on the other side of the world, off the coast of Africa. This was during the Battle of Cape Bon, where the Vandals were defending their new capital, Carthage (yes, that Carthage), against the combined fleets of the Eastern and Western Roman Empires. It was supposed to be the largest amphibious assault of the time – 1,113 ships, 50,000 sailors and soldiers – but the Vandals’ raiders prevented it. The Vandals burned and sank more than 100 Roman ships, and 10,000 Roman soldiers and sailors were killed. Without access to the resources of the African province, the Western Roman Empire was doomed.

As you can see, in ancient times, firebrands were a formidable force that led to the fall of empires. Perhaps this time, the firebrand’s descendants will overthrow another under-empire!

In the Middle Ages, brigands became a permanent part of the fleet and were not even converted from old ships, but were built specifically for this role. They were usually small, fast ships like brigs or sloops. By the way, they were the first ships in the world to have funnels! The funnels were used for better traction and to ignite flammable materials in the holds. Some brigs were equipped with boarding hooks.

Branders were used in the destruction of the Invincible Armada (1588), the Burning of Holmes (1666), the Battle of Solebey (1672), and the Battle of Barfler (1692). During the siege of Antwerp (1584-1585), the besieged used special brigands with explosives – Hellburners / Hellebranders. The Dutch rebels (again, these parallels, fighters for independence against the Empire) used these floating bombs, nicknamed “Antwerp Fire”, against the Spanish fleet and caused them enormous damage. Hellburners are even considered one of the first weapons of mass destruction.

By the way, the Dutch began using the word “brander” during the Eighty Years’ War (1568-1648), an uprising of seventeen provinces of the present-day Netherlands, Belgium, and Luxembourg against Philip II of Spain, the sovereign of the Spanish Netherlands. It was the peak of the Brander’s military career.

But even later, in modern times, brigands took part in the Battle of Navarino (1827), the Greek War of Independence (1821-1829), and even the American Civil War (1861-1865). The advent of metal steamships made the use of brigands impractical. They were replaced by bomb boats.

FL-boat / Fernlenkboot

The idea of Branders, or more precisely Hellebranders, was first mentioned during the First World War. Despite the availability of powerful long-range artillery and the active use of submarines and torpedoes, the idea of a high-speed boat filled with explosives that could even be remotely controlled seemed like a good one, and the German Imperial Navy authorized the development of the FL-Boat (Fernlenkboot, literally “remote-controlled boat” in German). As I mentioned at the beginning, it was almost a modern naval attack submarine, but using technologies from the early 20th century.

The 17-meter, 6-ton Fernlenkboote motorboats were built by Siemens-Schuckert (yes, the company is now simply called Siemens). Equipped with two Maybach engines of 210 hp (154 kW) each, the boats could reach speeds of up to 30 knots (56 km/h) and carry 700 kg of explosives. At the time, this was state of the art technology – remote control by wire from a shore station (there were plans to install a station on ships) and radio control by UAVs from airplanes. The range was limited by the length of the cable – 20 km. The cable reel weighed 800 kg!

The following commands were available to the operator: test the system; start/stop the engine; adjust the steering wheel position; turn on the searchlights for night use; remote detonation if enemy capture was imminent.

The plan was to use the Fernlenkboot against slow or stationary British monitors off the coast of Flanders. A total of 17 of these steampunk UUVs were built.

During the Fernlenkboot test, the concept was shown to be viable, but in actual use, it turned out that the correction delay interfered with accurate targeting. In addition, 20 kilometers was not enough; the main calibers of World War I battleships had a range of 20-25 kilometers and even more.

Therefore, there are only a few examples of successful use of Fernlenkboot. On March 1, 1917, one FL-boat hit the breakwater of Nieuwpoort (Belgium), and on October 28, 1917, another FL-boat hit the monitor of HMS Erebus. The monitor was slightly damaged, and about 15 meters of anti-torpedo blister, a kind of passive additional armor near and below the waterline, was lost.

After World War I ended, kamikaze boats were forgotten… until the next great war.

Motoscafo da Turismo

The concept was revisited in Italy in 1939, but this time they decided not to bother with remote control but to rely on a man at the helm. But unlike the Japanese vehicles of this type, there was no question of kamikaze, the creators of the concept believed that the pilot would be able to jump out after the boat was pointed at the enemy and have a chance to escape.

The Motoscafo da Turismo and the improved version of the Motoscafo da Turismo Modificato (yes, that’s Italian for “modified tourist motorboat”, you guessed it), also known as barchino (Italian for “small boat”), were 5.62 m long, weighed 2 tons, and thanks to an Alfa Romeo AR 6cc engine (95 hp or 71 kW) could accelerate to 33 knots (61 km/h) on the last stretch. The payload was 330 kg of explosives.

The MT/MTM deployment scheme was quite interesting. The boats were launched from the mother ship, crossed the anti-torpedo barriers of the harbor in “quiet mode”, headed for the target, and only then turned on the engine at full power. The pilot jumped out, there was even a kind of primitive catapult, and the seat turned into a small life raft. Upon impact with the target, the hull of the MT was destroyed by an auxiliary charge, the boat began to sink, and a special detonator was triggered 1 meter underwater. The underwater explosion was designed to increase the damage to the target’s hull, and the raft was designed to help the pilot stay on the surface to avoid the underwater shock wave.

The most successful example of the use of the Motoscafo da Turismo was the raid on Souda Bay (Crete) on March 26, 1941. Two Italian destroyers, Francesco Crisri and Quintino Sella, had 3 MT boats on board. The boats were launched at 23:30 on March 25, 16 km from the target and reached the port an hour later. Two MTs hit the heavy cruiser HMS York (standard displacement 8,380 tons) and the crew was forced to run her aground. York never saw action and was broken up for scrap in 1952. Another MT hit the Norwegian tanker Pericles, which was badly damaged and sunk. Other MTs, according to the British, did not hit their targets, while the Italians say another tanker and a cargo ship were damaged. Interestingly, all six MT pilots escaped and were captured.

But the raid on Malta on July 26, 1941 was completely unsuccessful. Six MTs were launched from the sloop Diana according to the same scenario as in Souda Bay, but this time together with other ships of the Mosquito Fleet. The battle group was detected by British radar in advance and destroyed by coastal defense guns as they approached the target at close range. Only one MT hit the St. Elmo Bridge, which connected the pier over Malta’s Grand Harbor to the shore. Interestingly, the bridge was only rebuilt in 2012; for 70 years, the lighthouse on the pier was accessible only by boat.

On June 29, 1942, several MTMs took part in the German landing near Balaklava in the Crimea… what an interesting coincidence.

In 1943 the Motoscafo da Turismo Ridotto appeared, a lightweight version for use from submarines, but the only attempt to use them ended before it began when the submarine Ambra with an MTR on board was damaged by a British plane.

In total, about twenty MT, MTM and MTR were produced, and several of them even survived the war. Four of these boats went to Israel and participated in the 1947-1949 War of Independence (here we go again!). On October 22, 1948, Israeli MTs launched from the patrol ship INS Ma’oz attacked the sloop El Amir Farouq and the BYMS-class minesweeper of the Egyptian Navy. The El Amir Farouq sank in five minutes and the minesweeper was heavily damaged and written off. All pilots were rescued by the Israeli Navy.

Shin’yō

In 1944, Japan became interested in the concept of attack submarines, but no one in that country wanted to rescue the pilot; these were real kamikaze drones. Although it was theorized that the crew, in some versions there were two crew members, could be rescued.

Depending on the modification, the Shin’yō boats weighed 1,295 or 2.2 tons and were 5.1 to 6.5 meters long. Two Toyota engines of 67-134 hp each provided a speed of 26-30 knots (48-56 km/h). The range was 200-315 km. In addition to 270 kg of explosives in the bow, the boats also carried two 120 mm unguided anti-ship missiles.

A total of 6,197 Shin’yō boats were produced from April 1944 to June 1945 out of a planned 11,300. Most of them were intended for defense of the Japanese coast in the event of an American landing, but some boats were used in the Philippines and Okinawa.

By the end of the war, Shin’yō boats had damaged or destroyed 24 enemy landing craft and light vessels. The largest kamikaze “hauls” were the damaged destroyers USS Charles J. Badger (DD-657) and USS Hutchins (DD-476). None of the attacks on large ships were successful, as the United States already had radars that negated the surprise factor.

The United States captured a large number of undamaged Shin’yō after Japan surrendered, but was not interested in these weapons. And with good reason.

On October 12, 2000, terrorists (Sudan is now believed to be the perpetrator) sailed an explosives-laden boat to the destroyer USS Cole (DDG-67), which was refueling in the port of Aden, Yemen, and detonated an explosive device. 17 sailors were killed, 37 others were injured, and the ship almost miraculously did not sink. The destroyer was repaired and is still in service.

But the USS Cole was an isolated act of terrorism. During the Cold War, the era of anti-ship missiles arrived, and motorboats with explosives were long forgotten.

Unmanned Surface Vehicle

Nikola Tesla received a patent for a radio-controlled boat back in 1898 and even demonstrated an experimental model of his Teleautomatics to the public. Unfortunately, the US Army was not interested in a radio-controlled torpedo at the time. The German Fernlenkboot also remained rather one of the military curiosities of the First World War, which were really plentiful at the time. The idea of unmanned surface vehicles (USVs) was returned to only in the twenty-first century, and with satellite communications and GPS, there were no longer any problems with remote control.

Both civilian (autonomous cargo ships, oceanographic, hydrographic drones, etc.) and military developments have been going on at a rather slow pace since the mid-2010s. But the military of the United States, Turkey, Israel, and other countries are creating primarily light patrol, mine countermeasures, and reconnaissance platforms, and, as a last resort, boats with light missile and small arms. There are exceptions, for example Sea Hunter and the Ghost Fleet Overlord program, but these are only prototypes and experimental ships.

The outbreak of a full-scale Russian-Ukrainian war has refocused attention on motorboat-based maritime attack drones.

Ukrainian naval strike drones

At the start of the full-scale invasion, Russia had complete control over the Black and Azov seas. The Armed Forces had neither ships that could harm Russian ships, nor anti-ship missiles (well, there was almost no 🙂), no opportunity to use aviation. So the idea of creating a fleet of naval attack drones is in some ways a gesture of desperation, but also a rather unexpected, daring, and relatively inexpensive move that took the Russians by surprise.

The first public appearance of a Ukrainian maritime attack drone was on September 21, 2022, when an unknown unmanned surface vehicle was found near Sevastopol. According to an analysis by the US Naval Institute, it was a Ukrainian weapon assembled from parts of a commercial jet ski. It appears to have used a Starlink terminal to communicate. The mere appearance of the drone frightened the Russians, who withdrew the extra ships from the external attack and hid in Sevastopol Bay.

But it didn’t help. Already on October 29, 2022, ships of the Black Sea Fleet of the Russian Federation in Sevastopol Bay were attacked by UAVs and 7 naval attack drones. Several ships were reportedly damaged in the attack, including the minesweeper Ivan Golubets and the missile frigate Admiral Makarov.

In November 2022, Ukraine officially announced the creation of a fleet of maritime drones on the United24 platform, at the same time the characteristics of these devices became known. The plan was to build 100 of these power supplies.

Technical specifictions of Ukrainian 1st generation attack marine drones
Length – 5.5 m
Gross weight – up to 1000 kg
Operating radius – up to 400 km
Range – up to 800 km
Autonomy – up to 60 hours
Combat load – up to 200 kg
Maximum speed – 80 km/h.
Navigation methods – automatic GNSS, inertial, visual
Video transmission – up to three HD video streams
Encryption crypto protection – 256 bits
Unit cost – 10 million UAH

The next attacks by Ukrainian submarines on Sevastopol Bay took place on March 22 and April 24, 2023. This time, it seems, they were less successful, but it was enough to keep the Russians on their toes and prevent operations on the high seas.

On May 24, 2023, the Russian reconnaissance ship Ivan Khurs was attacked by three maritime drones 140 km from the Bosphorus. Unfortunately, we have no reliable data on the results of this attack. On June 11, 2023, the Russian reconnaissance ship Priazovye was attacked. This happened 300 kilometers southeast of Sevastopol, and unfortunately, the consequences are also unknown. But these two attacks demonstrated to the enemy that Ukraine has weapons that can hit a target in any part of the Black Sea.

On July 17, 2023, at 03:04 and 03:20, explosions occurred on the automobile part of the Crimean Bridge, one of the pillars and a span were destroyed. According to experts, the bridge was hit during a joint operation by the SBU and the Ukrainian Navy, and MAGURA V5 drones, which are the second generation of Ukrainian strike drones, took part in the raid.

Finally, on August 4, 2023, the Russian large landing ship Olenegorskiy Gornyak was damaged in Novorossiysk Bay . Unfortunately, it did not sink, but received a huge hole in the hull and was put undergoing lengthy repairs. Next, on the night of August 4-5, 2023, a Sig oil tanker was attacked near the Kerch Bridge, supplying jet fuel to the Russian armed forces in the temporarily occupied Crimea.

All the attacks used drones with slightly different bodies, so we can assume that there are actually more than two configurations of Ukrainian strike UAVs.

Currently, it is Ukrainian engineers and military personnel who have the most experience in creating and using maritime strike drones. We are confident that development is ongoing, and soon we will see the third, fourth and fifth generations of Ukrainian UAS in action, the glorious descendants of the same branders that have long been the weapon of choice for independence fighters and helped destroy empires. Following the news!