Edit, 5/14/2019. Since some readers may view this blog as a compilation, Reuters) U.S. believes Iran proxies may be behind tanker attacks, official says. Quoting,
U.S. national security agencies believe proxies sympathetic to or working for Iran may have attacked four tankers off the United Arab Emirates rather than Iranian forces themselves, a U.S. official familiar with the latest U.S. assessments said on Tuesday.
This may derive from counting the Gadhirs in their berths, and other kinds of technical collection.
If the tankers were stationary, a dhow run by a proxy is very feasible. But since a dhow is typically a slow boat, only a little faster than a tanker, precise navigation and some luck would be required for a moving interception. Would a modern hull planer be noticed?
The original post:
Is there something more we can tease out of open source? A template based on the recent past gives insight into Iranian tactics, which emphasize surprise, asymmetry, and deniability.
There is indication that at least some of the attacks occurred while the tankers were under way. The locations, just outside the Strait of Hormuz, are convenient to Iran’s main naval facility, Bandar-e-Abbas. (Global Security) Yono Class / Ghadir Class Midget Submarine has plenty of detail.
What weapon was used? An unconventional answer is almost anticipated. While Iran’s engineering is third-rate, their tactical ingenuity is first-rate.
Supertankers are very hard to sink. Mine hits have occurred unnoticed by the crews. The damage level of these attacks does not exclude the typical weapons of naval warfare, mines and torpedoes. But strict deniability requires that the weapon contain little more than the explosive charge, and a little miscellaneous steel. More than that leaves a residue that could be fished out for forensics.
For a possible solution, we must reach back to the U.S. Civil War, when the modern self-propelled “torpedo” did not yet exist. The spar torpedo was an explosive charge on the end of a stick. It was rammed into the target ship, and exploded not instantly, but shortly after the attackers got away. Just before World War II, the Brits invented the limpet mine, which holds fast to the target with a magnet.
These are examples of weapons which leave behind little in the form of traceable scrap metal. Both are historically associated with midget (or littoral) submarines such as the Ghadir.
The following example stems from no particular insight, but is offered as an example of almost endless variations of improvisation. The Ghadir can also carry an underwater diver delivery vehicle. Though tankers move slowly, a diver still risks getting caught in the wake of the tanker. (At 15 knots, a 1000 foot tanker passes a fixed point in about 40 seconds.) An Iranian choice might be to tether the divers, or divers /vehicle, to the submarine with a rope, and go into reverse after the attachment. Or they could have put a limpet on the end of a stick.
Iran’s strategy now has another data point, suggesting that the missiles-on-dhows are reserved for reaction to overt retaliation by the U.S. Yet Iran’s loss of oil revenue is so severe that only very significant setbacks might deter their strategy, which now appears to be grinding, deniable attrition. Iran assumes that most U.S. weaponry is not suited for deniable use.
Yet the cupboard is not entirely bare.