On November 8th two American warships in the Gulf of Oman intercepted and searched a fishing boat headed for Yemen. The ship was coming from the nearby port of Jask in western Iran. Jask had become the main location where smuggler ships were loaded with hidden cargo for Shia rebels in Yemen. After a search that took a week, the well-hidden cargo of 70 tons of ammonium perchlorate (used for rocket fuel) and 100 tons of urea fertilizer (used for explosives) was found. This was the first time the international naval blockade of Yemen had discovered a smuggler transporting rocket fuel. The Shua rebels were getting this stuff for years and it was unclear how Iran was getting it to Yemen.
Smuggled weapons include, since 2017, Iranian naval mines and some crude locally fabricated naval mines. The naval mines are a recognized danger to all ships and in early 2020 shipping companies warned their ship captains that naval mines, of the contact type, were floating into the Red Sea from the north Yemen coast. That coast is off the Shia rebel home province of Sadaa and the rebels had been releasing groups of moored and un-moored mines in an effort to disrupt Red Sea shipping traffic to Yemen and Saudi Arabia. The currents generally flow north in this part of the Red Sea, towards the major Saudi Red Sea port and the entrance to the Suez Canal. The Shia rebels would drop Iranian moored mines into the sea at night. These mines are designed to have their weighted base sink to the bottom of shallow (less than 20 meters) water. A chain is used to keep the mine near the surface. Some of these contact mines were released to float on the surface while others had their chains break, turning the moored mine into a free floating one. These mines proved most dangerous to Yemeni fishing boats, including the ones Iran used to smuggle weapons in. Dozens of fishermen were killed when their boats hit one of these contact mines. These mines are a danger to the blockade warships as well as commercial shipping. Most commercial shipping is moved in very large ships which the contact mines inflicted minor hull damage. During 2020 there was a major effort to locate and neutralize these free-floating mines. By the end of 2020 over 160 mines were found and neutralized. The rebels continued putting mines in the water during 2021 and the number found and neutralized remained at 2020 levels. The Shia rebels continued putting these mines in the water after the 2022 American announcement that they would stop treating the rebels like a terrorist organization. That didn’t work and the mines and bomb boats continued to be used, but in smaller numbers. The use of naval mines has diminished because they are not much of a threat to warships (which are constantly on the lookout for them) and commercial ships that are too big to sink with these mines.
The floating contact mines are a 19th century development that has been improved on for over a century and is still used because it is cheap and effective. Iran has provided the Shia rebels with these mines. American warships are part of the international naval blockade of Yemen, to prevent smuggling and to deal with Shia rebel efforts to disrupt naval traffic in the Red Sea using remotely controlled bomb boats as well as naval mines.
Iran has acquired a stockpile of 3,000 to 6,000 mines, mostly of Soviet/Russian, Chinese or North Korean origin. Most are unsophisticated but still dangerous bottom-moored buoyant contact mines, like those that damaged several American warships in the Persian Gulf during 1991. These mines had been released by Iraq. Iran's current arsenal of sea mines is estimated to number around 2,000, and includes the domestically produced Sadaf-01/02 bottom-moored contact mines as well as more sophisticated bottom mines that lie on the bottom in shallow water with battery-operated sensors to detect ships passing over head and detonate when a ship of the desired type to be sunk by the bottom mine passes overhead. These mines put a hole in the bottom of the ship, which causes serious flooding that often sinks the ship. Naval forces with the right equipment can easily find and disable these bottom mines and that’s what happened to the bottom mines Iran supplied the Yemen Shia rebels with. The rebels had few of these bottom mines and apparently no more were smuggled in.
Iran continues to supply the rebels with GPS controlled UAVs that are turned into flying bombs for attacks on targets in Yemen and Saudi Arabia. At times the attacks on Saudi targets are particularly heavy. There was one day when Saudi air defenses detected and destroyed 17 of these UAVs, which the rebels did not try to use in swarm attacks to overwhelm air defenses. This often works inside Yemen, but rarely against Saudi targets. Iran smuggles the disassembled UAVs into Yemen on fishing boats and dhows (similar in size but just carrying cargo), where the components are easier to conceal. Some of these have been found. A growing number of smuggler boats are discovered because the Americans have developed a system for tracking such boats coming out of Iranian ports, particularly Jask, which is currently the main port where fishing boats and have their smuggled cargo carefully hidden. The Americans have also been obtaining more information from inside Iran about the techniques for hiding smuggled items. All this costs Iran a lot of money. They have to pay shipyard technicians to modify the boats to carry smuggled cargo. The crews of these boats are also paid a lot for the risks of getting caught and jailed. Iran has been short of cash since economic sanctions were revived in 2020 and the higher cost of preparing the boats and bonuses for the crews limits the amount of smuggled cargo that reaches the Yemen rebels.
IRGC leaders were reluctant to give up gains made in Yemen and may have been told that they could revive support for the Yemeni Shia after the economic sanctions on Iran are lifted. Because of these sanctions Quds force saw its budget cut by half since 2017, forcing major reductions in Quds activities in Iraq, Syria and Lebanon. Yemen was always the least expensive Quds operation and did not suffer noticeable aid cuts. Yemen was the only IRGC operation that was able to attack arch-enemy Saudi Arabia directly and that counted for something. The Yemen operation was allowed to continue. The new (since January 2021) American government believed they could negotiate an Iranian departure from Yemen, Iraq and Syria. So far, Iran has refused to consider giving up their operations in places like Yemen.
Iran had already found an effective way to attack Saudi Arabia by arming Shia rebels in Yemen with over a thousand ballistic missiles and UAVs since 2016. Most of these were aimed at southwestern Saudi Arabia. Less than one percent of those UAVs and missiles hit anything of consequence in Saudi Arabia. Iran is seeking to carry out a similar campaign against Israel using Iran backed militias in Syria. That has not been working out so far because Israeli intelligence capabilities and airstrikes have been much more effective in Syria than Saudi efforts in Yemen. This despite the fact that Israel and Saudi Arabia have similar aircraft, smart bombs and air defense systems.
While not as efficient as the Israelis, Saudi pilots and ground forces have gained a lot of practical combat experience in the last six years. Saudi pilots are much more accurate and surer of themselves than they were during the first two years (2015-16). On the ground the Saudis supply artillery and troops trained to quickly and accurately request and direct air and artillery support. All these ground teams have a year or more of combat experience and it makes a difference.