Houthi rebels sustain threat to commercial shipping

On April 3rd, Houthi rebels launched an unspecified missile in the direction of a Saudi oil tanker, identified as the super tanker Abqaiq carrying two million barrels of oil. The vessel was attacked in international waters near the port city of Al Hudaydah, but a Saudi naval vessel in the area was able to intercept the missile before its impact. The Abqaiq reportedly suffered minor damage in the incident, and was able to continue its journey under escort of the Saudi Navy. Even though no significant damage was done, the incident highlights the continued threat to commercial shipping in the Red Sea as a consequence of the conflict in Yemen.

Houthi rebels claimed they had fired the missile at a Saudi naval vessel, in retaliation of a bombardment in Al Hudaydah the day before, though both the Saudi navy and EU NAVFOR identified the target as a commercial oil tanker. It is possible, that the Houthi rebels were trying to target a Saudi naval vessel, and mistakenly targeted the oil tanker. In the past the threat of anti-ship missiles fired by Houthis has targeted naval vessels belonging to the United States, the United Arab Emirates and Saudi Arabia. Directly targeting an oil tanker would be a big shift, though this current incident shows that even if this is not the immediate intent, there is still a significant risk to commercial shipping through the use of anti-ship missiles by Houthi rebels.

These missile attacks are part of the limited methods the Houthi rebels have available to challenge the blockade of the major ports of Yemen by the Saudi led coalition. The exact type of missile used in the current attack is as of yet unknown, but previous missile attacks against naval warships off the coast of Yemen involved the use of C-801 Silkworm anti-ship missiles.The first attacks of this type were conducted between October and December of 2015 but failed to hit any ships passing along the Red Sea coast. A more successful attack took place on October 1, 2016 when the catamaran HSV-2 Swift in service of the United Arab Emirates was hit by a C-801 anti-ship missile.The catamaran lacked the necessary point defense weapon systems needed to intercept the anti-ship missile at the time of the attack. Most of the ship was destroyed as a result of the fire that broke out following the impact of the missile. Another attack on October 12, 2016 targeted the US Navy destroyer USS Mason, but the missiles were intercepted before impact.

No new missile attacks were conducted following a retaliation strike of the USS Nitze on October 13 against radar sites used to guide the C 801 anti-ship missiles. It appears that in the absence of these radars, the Houthi rebels were unable to effectively target vessels in the Red Sea. In addition to this, coalition operations in the coastal areas of Taiz also denied Houthi control over some of the coastal areas that were used to launch these missiles. However, in November 6, 2017 the Houthi rebels announced they had produced their own anti-ship missiles, which they refer to as the Mandab-1. Images released by the Houthi rebels showed five missiles, which appeared to be almost identical to the C-801 Silkworm, painted in a previously unused light blue color scheme. The Houthi rebels are known to reengineer old stockpiles of missiles, such as the SA-2 surface to air missile that they use to produce their Qaher-1 and Qaher-2M ballistic missiles. The renaming of C-801 missiles, or closely related variants, to the Mandab-1 could point to actual modifications of the missiles. It is unlikely these missiles were produced indigenously, however, and the Mandab-1 may simply be cover for an arsenal of newly smuggled C-801 type missiles possibly originating from Iran.

So far, neither the rebels or the Saudi led coalition have confirmed the type of missile used in the attack. The large time delay between the previous attacks suggest that the Houthi rebels no longer had a true capability to target naval vessels in the Red Sea, either by being denied the use of larger radar systems, by having depleted their stockpile of C-801 missiles, or due to pressure from ground operations in coastal areas. If the missile used in the attack was indeed a Mandab-1, this newly emerged stockpile of C-801 based missiles could have renewed this Houthi capability to target vessels in the Red Sea..

The use of anti-ship missiles by the Houthi rebels has proven to be the most potent weapon it has against the Saudi led coalition warships. These missiles themselves are part of a larger arsenal. Houthi rebels have also used explosive laden boats and floating naval mines to disrupt naval operations in the littoral waters off Yemen, though their effectiveness has so far proven to be limited.

The use of the so called Shark-33 remote controlled explosive laden boat was used in a  notable attack against a Saudi Al Madina class frigate on January 30, 2017. The Shark-33 struck the frigate near the helicopter hangar but caused only slight damage and the ship was able to head back towards its naval base by its own strength. Other attacks using this type of system targeted shipping in the port of Mocha following its liberation by the Saudi led coalition, but failed to destroy any shipping.

Floating naval mines have been used by Houthi rebels mostly in the waters near Midi, most likely in an attempt to have the current drift them northwards towards the port of Jizan. None of these naval mines were reported to have damaged any vessels near Midi or Jizan and regular patrols by the Saudi led coalition and Yemeni coast guard result in regular interceptions of mine laying vessels and boats used by the Houthi rebels. So far the mines have only managed to damage a Yemeni patrol boat near the port of Mocha on March 10, 2017.

The Saudi led coalition has so far been able to counter most maritime threats posed by the Houthi rebels. Aircraft of the Saudi led coalition are said to strike suspected weapon depots allegedly containing anti-ship missiles, as well as striking suspected explosive laden boats in Houthi controlled ports. Regular patrols off the coast of Midi by the Yemeni coast guard limit opportunities for the Houthi rebels to lay naval mines in these waters while any detected naval mines are swiftly defused using explosive charges. Houthi rebels in their turn have tried to disrupt these patrols and often conduct raids with fast boats and small arms against these patrol vessels, but so far they have been unable to deter these patrols..

The Saudi led coalition has clearly done a lot to mitigate the threat against commercial shipping or naval vessels operating in the Red Sea, but the Houthis continue to show an intent to target shipping. They may not intentionally target commercial shipping, but the methods they use clearly also put commercial shipping at risk. The development of systems such as the Mandab-1 shows that continued Houthi intent, as well as attempts by the Houthi rebels to overcome the attempts by the Saudi led coalition to prevent attacks against shipping.