The 90mm AMTB Guns
Anti Motorized Torpedo Boat Guns
Technically known as the 90mm M3 fixed
mount, the AMTB gun was the fixed mount version of the
army’s 90mm anti-aircraft gun. Used in the coast defense
roll, the 90mm M3 was supplied with a heavy shield on three
sides and remote fire control for use against high speed
craft. Due to their speed and great maneuverability, it was
feared that these craft could slip past the large coast
defense guns and possibly attack the inner harbor.
Sixteen guns were deployed around the Los Angeles and Long
Beach harbors during world war two at the Gaffey Bulge on
the Upper Reservation, Navy Field on the Middle Reservation,
at the tip of the Coast Guard base on Terminal Island, and
at Bluff Park in Long Beach.
Out of hundreds of guns of this
type that were built during the war, only a handful of them
survive today. In 1992, through the help of the
Coast Defense Study Group, the National Parks Service
transferred one of the surviving gun mounts with its shield
to the Fort MacArthur Museum. The gun is missing from the
mount and both the mount and shield have been left exposed
to the elements for years. Both pieces will require
substantial work to make for a safe and functional exhibit.
Volunteers are welcome for this project but to really get
started, we need to locate a 90mm barrel from either another
AMTB gun or anti-aircraft gun.
There is a second mount with a barrel on an Air Force base
in Alaska and a third at Fort Monroe, Virginia that belongs
to the US Army Casemate Museum. The Fort MacArthur Museum is
working with the US Air Force to reach an agreement that
would allow us to recover the gun in Alaska. Some of these
guns were also shipped to other countries after the war and
may still exist in foreign inventories.
If you should happen to come across a 90mm gun in your
travels, we urge you to contact the museum and let us know
were you found it.
The 90mm AMTB mount
at Gaffey Street Bulge
The 90mm AMTB mount
at Gaffey Street Bulge, north.
At one time the City of Los Angeles had mounted a "tourist