inside the SLC. A JAU-1/B cartridge is installed in the
SLC, and the loaded SLC is installed in the sonobuoy
launcher aboard the aircraft.
To launch the Mk 25 marker, the JAU-1/B cartridge
is initiated through the aircraft circuitry. It develops
sufficient gas pressure inside the SLC to force off the
SLC end cap and expel the foam spacer assembly
containing the Mk 25 marker. Once out of the SLC, the
split foam spacer assembly is separated by the airstream,
freeing the marker. The airstream then separates the
Mk 34 adapter kit from the marker, allowing them to fall
to the water as separate units. Upon entry into the water,
the marker functions as previously discussed.
MK 58 MOD 1 MARINE LOCATION
MARKER
The Mk 58 Mod 1 marine location marker (fig.
4-11) is designed for day or night use in any condition
calling for long-burning, smoke and flame
reference-point marking on the ocean’s surface. In
addition to being used for antisubmarine warfare, it is
used for search-and-rescue operations, man-overboard
markings, and as a target for practice bombing at
sea. The marker produces a yellow flame and white
smoke for a minimum of 40 minutes and a maximum of
60 minutes. It is visible for at least 3 miles under normal
operating conditions.
Physical Description
The Mk 58 Mod 1 marine location marker consists
of a cylindrical tin can approximately 21.78 inches long
and 5.03 inches in diameter. The can contains two
pyrotechnic candles of a red phosphorus composition.
The ignition end of the marker has three holes-two for
smoke and flame emission and one for water to enter the
Mk 72 Mod 1 seawater-activated battery. Adhesive foil
disks hermetically seal the two emission holes. A
reinforced adhesive foil strip with a rectangular pull ring
hermetically seals the battery cavity hole. The adhesive
foil seals are protected during handling and shipping by
a replaceable polyethylene protective cover.
Launching Methods
The Mk 58 Mod 1 marker maybe hand launched,
externally launched from suitable aircraft bomb racks
by using breakaway suspension bands, or launched from
sonobuoy launchers by using a sonobuoy launcher
container (SLC) and the appropriate foam spacer. No
matter how the marker is launched, the protective cover,
the pull ring, and reinforced adhesive foil strip over the
battery’s cavity are removed.
When launching the marker from a sonobuoy
launcher, you remove the protective cover and pull ring
and reinforced adhesive foil strip. Then, load the
marker onto the bomb rack. After securing the marker
Figure 4-11.—Mk 58 Mod 0/1 marine location marker.
4-12
