Launching Methods
Currently, there are two methods of launching the
Mk 25 marker—by hand or by sonobuoy launcher. To
launch by hand, rotate the base arming plate clockwise
to the armed position. Push the base plugs into the
battery cavity, located in the marker base, and throw the
marker into the water. It functions as previously
discussed.
If the base plugs (one or both) of a marker are
disturbed so the watertight integrity of the battery cavity
is compromised and the marker is not launched im-
mediately, a marine marker adapter kit (Mk 34 Mod 0)
must be installed. The Mk 34 Mod 0 adapter kit is also
used when the marker is launched from sonobuoy
launchers. The adapter kit fits over the base end of the
marker, and, when properly installed, seals the battery
cavity. The adapter kit is installed by rotating the marker
base arming plate to the armed position and pushing the
base plugs into the battery cavity. Remove the black
G-ring and install the adapter kit around the marker base
so the seal plugs on the leaf-spring ends cover the holes
into the battery cavity. Insert the U-pin to hold the
adapter in place. To hand-launch a marker with a
Mk 34 adapter kit installed, remove the U-pin and the
adapter and throw the marker into the water.
Before launching the Mk 25 marker from sonobuoy
launchers, you should install a Mk 34 adapter kit (fig.
4-10) on the marker. The adapter kit provides a safe
environment for the marker until the last possible
moment before launch. Because of the physical
difference in size between the Mk 25 marker and the
sonobuoy launch tubes, a sonobuoy launch container
(SLC) and spacer assembly (fig. 4-10) is used to launch
the Mk 25 marker from a sonobuoy launcher.
The Mk 25 marker, with the Mk 34 adapter kit
installed, is installed into the cavity half of the split foam
spacer assembly section with the U-pin of the Mk 34
adapter in the UP position. Then, remove the U-pin and
place the other half of the split foam spacer assembly
section over the marker, which completely encloses the
marker. The foam spacer assembly containing the
marker is then installed into the SLC against the
obturator. Foam pads are installed, and the end cap is
locked into slots in the SLC, retaining the assembly
Figure 4-10.—Spacer assembly and sonobuoy launch container.
4-11
