US/Israel conduct airstrikes on Iran again

It will certainly help. The biggest threat to shipping isn't so much Iran's arsenal of conventional missiles, but attacks by fast boats of the Islamic Revolutionary Guard Corps (IRGC). In a series of posts a week ago, I outlined how the naval arm of the IRGC basically specialises in naval "guerrilla warfare", using speedboats and other small craft to attack shipping, lay mines, etc.. Back then, I mentioned that I could see the 31st MEU, the self-contained US Marines task force that had just been sent to the gulf from Okinawa, might be used to go after some of the IRGC's operating bases around the Strait of Hormuz. My post from a week ago goes into some of the details as to why the 31st in particular might be a good choice for such an operation.

Now, the IRGC's naval arm has a "lot" of assets, we're talking about between 3000 and 5000 boats in total. Some of these are large-ish, comparable to corvettes or small offshore patrol vessels, but the vast majority of these boats are small speedboats with a displacement of less than ten tons, maybe 10-15 meters long and manned by a handful of crew members. These boats are fast, upwards of 50 knots or around 80-90 km/h, but they are short ranged and more importantly, they are fragile, and not really suited for operations in the open ocean. That basically restricts their operations to the Persian Gulf and the Strait of Hormuz, more precisely the western part of the Strait, since that is sheltered from the oceanic swells that affect the eastern part, which is open to the Arabian Sea. And it means that these boats can't stray too far from their bases due to fuel constraints.

Above is a Google Maps screenshot of the western part of the Strait of Hormuz, with the UAE visible in the bottom right, and the Iranian mainland and the island of Qeshm at the top. There's a loose grouping of six islands in this area that form a "gauntlet" that shipping in the Gulf have to pass through in order to transit the Strait. I've marked them in yellow.

These islands are Sirri or Siri, Abumusa, which also lends its name to this group of islands, Greater & Lesser Tunb, and Farur. Interestingly, Abumusa and the Tunb islands are disputed between Iran and the UAE, a dispute that dates back to the time of the Shah, long before the Islamic revolution in Iran.

Sirri Island

Sirri Island is probably the most crucial island in the group, since it is the site of a sizeable oil terminal but otherwise unpopulated, with the only civilian infrastructure being related to worker's accommodation for people working in the oil terminal. The oil tanks of the terminal are clearly visible in the Google Maps screenshot above, as are the islands two harbours on the south.

The image above clearly shows the tanker pier with the piping and loading manifolds, as well as the presence of several offshore service vessels and tugboats in the protected parts of the harbour. However, it's the south harbour that is most interesting in my eyes.

It may look like an ordinary fishing harbour at first glance, of the type that are legion all along the Iranian coast, but if you look more closely, you'll notice that things don't quite add up. The boats tied up at the pier along the eastern breakwater all have long and pointed hulls, optimised for speed, not manoeuvrability or ruggedness, which you'd expect from a fishing boat. To me at least, these boats look like the type of speedboat used by the IRGC.

This is further reinforced when we look at a zoomed out image. These types of regularly spaced buildings aren't found in the fishing villages in the region, which are often centuries old and have grown organically. This regular structure, the presence of boat trailers parked in neat rows and the lack of any fishing boats dragged onto the shore just make it more clear that this is an IRGC base.

Abu Musa Island

As mentioned before, Abu Musa gives its name to the entire island group. It is located fifty kilometres east of Sirri Island and unlike its neighbour, it actually has a civilian population, around 2100 people according to Wikipedia. The island is disputed by the UAE and Iran, and have been occupied by Iran following a landing of Iranian forces in 1971. The conflict is unresolved to this day.

The island isn't exactly big, the 2900 meter runway of the airport spans almost the entire width of the island. Much of the island's civilian housing and infrastructure is located to the north of the airport runway, whilst the civilian harbour is located on the westernmost edge of Abu Musa. The East harbour is not civilian however.

The east harbour is extremely sparse at first glance, but actually sports a surprising amount of infrastructure. There's a dedicated pier for larger vessels on the outer breakwater, a large pier housing numerous small boats on the southern breakwater, a boat lift, what looks like a headquarters building and a large blue-roofed shed that I believe to be a maintenance building. What's more, it is located in close proximity to a segregated apron and taxiway of Abu Musa Airport, one that hosts a number of covered aircraft stands that are typically associated with military or paramilitary operations.

If we look at the boat pier more closely, we can see that once again, the boats tied up here are optimised for speed, rather than utility. Moreover, the three vessels at the pier head look distinctly military. The tow narrower boats resemble, at least to my untrained eye, IRGC missile boats of the Peykaap class, whilst the larger boat at the very top looks like a more conventional patrol boat. Either way, the east harbour is definitely an IRGC base.

Greater & Lesser Tunb

I'm grouping these two islands together for brevity, this is going to be another long post anyway. These two islands sit about 48 kilometres northeast of Abu Musa, the body of water between them being the only stretch of water deep enough for supertankers on their way to transit the Strait of Hormuz. Greater Tunb has a small civilian population of around 300 people according to Wikipedia, but Lesser Tunb is completely uninhabited. Both islands are subject to a territorial dispute with the UAE.

Starting with greater Tunb, there's a familiar pattern emerging. Much of the civilian infrastructure of the island is located to one side of the island's airport, including a small fishing harbour on the island's south coast. Once again, the eastern harbour appears to be an IRGC base.

Whilst this harbour seems to lack the large boat lift seen at the Abu Musa base, the rest of the infrastructure is strikingly similar, with a pier for heavier vessels on the eastern breakwater, a slipway to get smaller boats into and out of the water, and a larger pier housing speedboats on the southern breakwater. This picture does show a dhow or similar civilian vessel tied up near what I presume to be the slipway, but this is a) not up to date imagery of course and b) the IRGC does fulfil coast guard like roles as well.

Lesser Tunb continues this general pattern, although the island does not appear to have any civilian population. The island sports a small airfield and a large harbour on its eastern tip, although this is much more sparse than the ones present on the other islands in the group.

Farur Island

I've had a hard time finding any information about Farur or Faror Island. It sits about 75 kilometres to the west of Greater Tunb and twenty kilometres north of Sirri, and currently has no civilian population, although it did have one in the past. Unlike the other islands in the group, it does not have an airfield and the harbour on its eastern coast is also rudimentary, although it does appear to have a large maintenance/workshop building.

Interestingly, Faror Island is listed as the home base for the IRGC's Sepah Naval Special Forces unit. This unit has been involved in a number of high profile ship seizures, including the Portuguese-flagged container ship MSC Aries, but has also been deployed to the Gulf of Aden on anti piracy operations, ironically operating alongside the US Navy.

It's also worth noting that these islands are all located relatively close to the IRGC Navy's Fifth District HQ at Bandar Lengeh on the Iranian mainland, which houses significant maintenance, repair and storage facilities. While I presume that this HQ was hit hard by the US during their strikes against Iran, the sparse infrastructure on the island bases makes them hard to take out with just airborne assets.

These five islands, especially Abu Musa and the Tunbs, form a gauntlet that is nigh-on perfect for choking off civilian traffic trying to leave the Gulf. They all host IRGC bases, most of them have airfields, but none of them have a civilian population large enough to pose a serious risk to any military operation. Whilst I continue to believe that these islands are not going to see much more than amphibious raids, especially given the 31st MEU's specialisation in fast boat operations that I mentioned in my earlier post, an amphibious landing on those islands would be much more doable than trying to take Kharg or Kish island.

It's also worth pointing out that whilst there are other IRGC bases further along the Strait, such as Shib Deraz on Qeshm island, or at Sarkhur Tahruyi on the eastern end of the Strait, the density of bases is nowhere near as high as in the Abu Musa group.