Notes: These huge hovercraft were built by BHC in Great Britain and based upon the commercial Wellington BH.7 Mk1 prototype. They are amongst the largest air-cushion craft ever built outside of the USSR.

The hull is of a corrosion-resistant lightweight alloy, with the bow section being a high-strength fiberglass. The cargo deck is spacious (183’7" long x 13‘7"" wide x 7‘8" tall centreline, tapering downwards) and served by a bow ramp which can accommodate things such as the Takavar jeep or Sanam-23 towed AA gun. The skirt is made of neoprene-jacketed nylon. Underneath the craft is a full-length wall and an amidships cross-hull wall, by this the "cushion" of air is divided into four areas in that a catastrophic failure of the skirt in one area will not cause immediate loss of all hovering.

The entire 3-man core crew sits in the wheelhouse, with the helmsman to the left, the captain to the right (he also navigates and operates the radar), and the engineer behind them. In practice almost always there is a trainee aboard as well, and on the missile versions one or two more men in the operations room in the cargo area. In the transport configuration, the marines travel in paratrooper-style aircraft seats with their gear stowed.

Control is via swiveling the propeller’s transmission pod. The two stern fins have no rudders and merely stabilize the vessel. There is an ingenious hydraulically-operated "skirt lifter" which counter-banks the craft during sharp maneuvers, to help the helmsman avoid a "crabbing" motion. Four small puffers are fitted one to each quarter of the vessel to aid in precision low-speed maneuvering.

These huge craft only need a single sailor to control them; steering is done by a foot pedal arrangement while forward motion is via a throttle. The fuel is carried in fore and aft tanks, a centre-ship pump allows the helmsman to pump fuel between them (much like the trim pump on a submarine) to keep the hovercraft on an even horizontal base. These craft hold 9 tons of aviation fuel for the gas turbine.

The gas turbine engine is mounted aft and exhausts out the stern transom, with it’s exhaust providing a tiny bit of residual thrust. The engine is directly linked to the 11’6" diameter lift fan and connected via alloy driveshaft to the propeller’s transmission pod. The British Aerospace drive propeller is immense, measuring 20’10" in diameter. There are two Lucas IS/90 auxiliary power units (APUs) in the stern, these power the hovercraft’s 110kV 400Hz AC electricity system. They also start the main engine.

These craft are all-weather however in Sea State 5 and above, they are limited to 30kts and less if sailing directly into the wind. They are buoyant and are equipped with four landing skids under the skirt.

(below: the crew performing maintenance on 106’s transmission)

The advantages of these large hovercraft is that they enable the rapid deployment of amphibious troops, almost as fast as by helicopter. They can land vehicles and towed guns which would be difficult if not impossible to move by helicopter. Compared to regular amphibious ships, they can land troops over beaches which are too steep or rocky to beach a normal vessel, additionally they can move overland to bypass beachfront defenses, inserting troops and equipment behind the defender’s front line. They are also useful for quickly shuttling men and material around the Persian Gulf. Naturally they are immune to torpedoes and contact mines, and they can outrun most of the gunboats used by the smaller Gulf navies.

The primary disadvantage is their immense operating costs; they are more akin to an airplane being constantly exposed to saltwater spray and sand than a normal ship. Their maintenance needs are measured in operating hours, not years between refit. As might be expected, controlling these unique, massive hovercraft takes special skill and as there are no trainers for hovercraft of this size, new crewmen can only be trained by expensive in-use hours of the vessels themselves.

There were three versions delivered to Iran; the baseline Mk.4, and the Mk.5 (with uprated gas turbine for hot weather) which came in both a general-purpose version and a version wired for missiles. This version had side embrasures for two Sistel Sea Killer anti-ship missiles which were never mounted. (Some sources incorrectly state that they were slated to receive RIM-66 Standard SAMs in box containers as carried on Iran‘‘s Gearing class destroyers).

The Imperial Iranian Navy’s hovercraft squadron was inaugurated on 29 July 1968; with the unit being sponsored by Princess Shahnaz Pahlavi. During the imperial era, the BH.7s were organized as a special squadron and based at Kharg island.

After the 1979 revolution which overthrew the Shah, it was assumed that these craft would quickly become unserviceable however the Iranians proved quite adept at maintaining them. The importance the Iranian navy apparently put into the class is shown that at the height of the Iran-Iraq war, precious resources were spent giving this class refits between 1984-1985, including overhauling the gas turbines, replacing the skirts, and correcting some hull corrosion.

The hovercraft base on Kharg island was destroyed during the 1980-1988 war with Iraq. Thereafter the Iranian hovercraft are homeported at Bandar Abbas.

In 1989, it appeared that only half were operational at any given time. By 1992, Jane’s Fighting Ships reported that all were once again fully operational. In 2006, the oldest two were put into caretaker status; given their age and high operating costs they are unlikely to ever see further service. Meanwhile Iran has apparently decommissioned all of it’s Winchester class hovercraft, freeing up additional manpower for the remaining four units of this class.

During the early 2000s, the two units which had been wired for the never-fitted Sea Killer missiles were refit to accept four Noor-1 anti-ship missiles in box launchers.

As hovercraft have largely gone out of fashion with most of the world’s navies by 2012, it’s quite remarkable that Iran has managed to keep these monsters going for so many decades, despite the war, sanctions, and revolution that other hovercraft-operating navies did not have to deal with.

(below: a unit of this class participating in a 2002 naval exercise)

All units of the class took part in the 1971 conquest of the Tunb islands. This chain of small islands in the middle of the Persian Gulf had been claimed by both the UAE and Iran since the late 1960s.

During the 1980-1988 war with Iraq, it does not appear that any of these hovercraft took part in the fighting.

Displacement: 54t at rest Dimensions: 78’3"x545’6"x0’’0" (skirt height 5’6") Machinery: Gas turbine (Mk.4) 1 Gnome 154M41 gas turbine (Mk.5) 1 Rolls-Royce Proteus gas turbine, 1 lift fan + 1 4-bladed CP drive propeller Max speed: 66kts (by 2012 reportedly restricted to 58kts in peacetime) Range: 620NM @ 60kts in Sea State 0 w/no load, 400NM @ 56kts in normal weather w/maximum load Endurance: 11 hours maximum normally, 3 days wartime maximum Complement: 3 (minimum required) / 5-6 (normal)

60 fully-equipped marines plus 14 tons of weapons/supplies/light vehicles; or 18 ½ tons cargo in maximum load configuration.

x2 Sea Killer (never installed)

(Current fit - 103 and 106 only)

x4 Noor-1                                      40NM surface

x2 M-2 Browning .50cal MG           ½ NM AA/surface

Decca 914 (I)                                  24NM surface search/navigation (ramge, bearing)