Bring in the BAT!

Throwback Thursday! On this day in 1945, a U.S. Navy PBY4Y-2 Privateer patrol bomber of VPB-109 employed “Bat” missiles against Japanese shipping off Balikpapan, Borneo in the effective first combat use of the only automatic homing missile to be used in World War II.

The squadron, though less than two years old, had already had an eventful war.

VPB-109 privateer

A VPB-109 Privateer

VPB-109 was established at NAS San Diego on 2 August 1943 as a heavy bomber unit flying PB4Y-1 Liberators under the operational control of  FAW-1, chopping to FAW-2 at NAS Kaneohe by November and moving up to the Gilbert Island chain by the end of the year. Scouting over Eniwetok and Wotje led to a transfer to Kwajalein Atoll in March 1944 from where they conducted numerous mining missions in the Truk Atoll and strikes against Oroluk, Ponape, Wake and Puluwat. This led to low-level photographic runs over Saipan and Tinian during the landings there that summer followed up by obligatory strafe and bombing missions.

They then proceeded to scratch the Japanese submarine RO-117 and raid Iwo Jima before heading back to Hawaii in August 1944 to switch over to PB4Y-2 Privateers. Shipping out after that on the jeep carrier USS Fanshaw Bay (CVE 70), they were selected in April 1945 to become the first unit to use SWOD Bat.

What’s a Bat?

BAT Air-to-Surface Guided Missile homes in on a target ship during tests. Photograph released 16 October 1946. National Archives photograph 80-G-703161. launched from PBM

That’s going to leave a mark. BAT Air-to-Surface Guided Missile homes in on a target ship during 1944 tests. The photograph released on 16 October 1946. National Archives photograph 80-G-703161. launched from PBM


The SWOD Mk.9 (Special Weapon Ordnance Device) Bat radar-guided glide bomb has been called, “arguably the most advanced of the early guided bombs” of the WWII era.

It was developed by the US Navy as a standoff anti-shipping weapon, with a secondary role of attacking coastal targets with good radar contrast, such as moored shipping, fuel storage tanks or warehouses. The Bat was the first fire and forget guided weapon, and the first radar homing anti-shipping weapon. It was a development of the “Pelican” glide bomb, which was equipped with a Receiving Homing Beacon (RHB) that required a radar beacon to illuminate the target.

The Bat used a Bell Telephone Laboratories developed S-band active radar seeker, and a 1,000 lb warhead with an impact fuse. The 1,700 lb weapon was released at medium to low altitudes and would home on its target once the seeker was activated. Tested by the  Naval Air Modification Unit (NAMU) in 1944, it was thought to have a 60 percent probably of hitting a ship.

Want more? Let’s tap in Gerald McRaney:

Squadron technicians were known as “The Batmen” and, deploying from Puerto Princessa, Palawan, VPB-109 got to work trying out the cranky new weapons.

BAT Missile is given a pre-flight checkup 16 October 1946. National Archives photograph 80-G-703165.

BAT Missile is given a pre-flight checkup on 16 October 1946. National Archives photograph 80-G-703165.

23 April: LCDR Hicks and LT. Kennedy dropped the first Bat weapons employed on a combat mission against shipping in Balikpapan harbor. Both devices were defective and did not strike any targets.

They soon worked the bugs out:

VPB-109 PB4Y-2 Privateer in flight with a Mark 9 BAT under each wing. Later ASM-N-2. NH 92485. Note heavily weathered color scheme

VPB-109 PB4Y-2 Privateer V527 in flight with a Mark 9 BAT under each wing. Later ASM-N-2. NH 92485. Note the heavily weathered color scheme and ERCO bow turret. 

28 April: Two of the Bat-equipped  Privateers flown by LCDR Hicks and LT. Chay again attacked shipping in Balikpapan harbor. Three Bats were released in an attempt to sink a large transport. Two of the Bats went to either side of the vessel, sinking two smaller freighters, while the third executed a sharp right turn to strike a large oil storage tank a quarter of a mile away in the Pandanseri Refinery, which the Dutch were probably happy about.

Although in the first week of May the squadron sank 45 Japanese vessels, though these were mostly small coastal craft unworthy of a Bat. This led the unit to be moved to juicier target areas off Okinawa, flying from Tinian. There, attacks by Bat-armed Privateers on 13, 15, and 16 May all failed due to defective missiles.

It turned out Bat was too sensitive to corrosion– so using it in the humid islands of the Pacific was probably a bad idea.

This, however, did not stop VPB-123 and VPB-124 from receiving the new weapons and using them briefly, though not very successfully.

In perhaps the Bat’s swan song, a VPB-109 Privateer flown by LT. Leo Kennedy crippled the 970-ton Japanese escort ship Aguni with a SWOD from 20 miles away while off the coast of Korea on 27 May then used dumb bombs to wipe out a 2,000-ton freighter and three smaller freighters in the same 90-minute action, winning the Navy Cross– which is perhaps the first U.S. decoration involving the use of an automatic homing missile.

In July, all of VPB-109, VPB-123, and VPB-124’s SWOD-specific “Batmen” were transferred to Combat Air Service Unit Seven (CASU-7),  Yontan Field, Okinawa, where the use of the Bat was consolidated moving forward and was to be carried by TBM Avengers and Curtiss SB2C Helldivers.

Apparently, the Navy tried using them to hit bridges late in the war but the early electronics couldn’t find them in the ground clutter. Then came the practical end of the war at the tail end of August.

As for VPB-109, the squadron was disestablished on 12 October 1945 in San Fransisco.

Aircraft is PB4Y-2 59522 VPB-109 (Miss Lotta Tail)

Aircraft is PB4Y-2 59522 VPB-109 (Miss Lotta Tail)

An excellent 69-page war book for the squadron is available online here (though BAT is only mentioned in like one sentence).

A U.S. Navy ASM-N-2 BAT radar-guided bomb mounted under the wing of a Consolidated PB4Y-2 Privateer at the Philadelphia Ordnance District during development and testing. (U.S. National Archives Photograph.)

What of the Bat you ask? Well, some 2500 of these primitive anti-shipping weapons were built but very few actually dropped before the end of the war. The Navy re-designated them the ASM-N-2 post-war and kept them in inventory until after Korea when they were replaced by more efficient air-launched weapons (ASM-N-7/AGM-12 Bullpup in the late 50s, AGM-45 Shrike in the 1960s and AGM-65 Maverick in the 1970s before Harpoon came around), then used them as targets.

When the Privateers went away, they were carried on Lockheed P2V-5, -6B, and -6M Neptunes as well as at least one Corsair:

BAT-Corsair nagts

We are betting you aren’t going to want to land an F4U with a center-line BAT on a carrier even though the 1,700-pound glide bomb was inside the Corsair’s 2,000-pound ordnance capability.

At least seven Bat airframes are still around:  one can be found at the Planes of Fame Museum (Grand Canyon AZ), one at the Admiral Nimitz State Historic Park (Fredricksburg, Texas), and one has just been refurbished at the NIST site (Gaithersburg, MD).


The number of Bats produced was rather large for their brief time in service. By comparison, some 6,072 AGM-84A air-launched Harpoons have been made since 1979 but they are arguably much more widely used.

Here is an interesting USAAF evaluation of the Bat over at Retro Mechanix.

The most enduring part of this story is the Casablanca-class jeep carrier, Fanshaw Bay, who carried VPB-109 and her Bats off to war. She wound up picking up five battle stars and a Presidential Unit Citation before entering red lead row in 1946. She lingered until scrapped in 1959– long after VPB-109 was disbanded and the Bats were removed from service.

Maybe she should be remembered as “The Bat Cave.”


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