VOLUME I Multinational Maritime Tactical Instructions and Procedures

MTP 1(D), Vol. I
SEARCH PLAN 1S
OAK TREE
Oak Tree is a search by ships in a loose formation
into which helicopters may be integrated. It may be used
as an area, intercept, lost contact or bottom search.
a. DIRECTING SHIP. The SAU commander or
SAC is the directing ship.
b. FORMATION. Units should be formed on a
loose line abreast. Distances between units and speed
are to be ordered by the SAU commander. Accurate
station keeping in this search is not necessary. The
SAU commander is to order and coordinate the deceptive
or evasive steering of the formation and/or individual
ships.
c. METHODS
(1) AREA SEARCH. An area can be
searched by:
(a) A SINGLE SWEEP through the area,
using a broad zigzag if necessary to widen the front.
This method could be used if the area is small, or if it is
desired to carry out a rapid but comparatively low probability
search.
(b) A SERIES OF SWEEPS in the form of
an expanding square search based on a datum or
search center. In this case units are required to be in a
loose line abreast. This provides a slow sweep rate.
(c) A SERIES OF PARALLEL SWEEPS
through successive portions of the area. This provides
thorough geographic coverage but a slow sweep rate.
(d) A SERIES OF RANDOM SWEEPS
within the area. This provides maximum deception
when it is believed that the submarine will remain within
the area.
(2) INTERCEPT SEARCH. Units search a
moving area. The position and size of the area at any
moment depend upon the estimate of the submarine’s
probable courses of action. This moving area can be
searched by a series of sweeps if the area is large and if
time permits. When intercepting a submarine assumed
to be closing a convoy or force, time is normally limited.
The requirement to keep the units between the submarine
and the force will in most cases permit only a single
sweep of the area.
(3) LOST CONTACT SEARCH. This
method is used in the following cases:
(a) When the submarine would be
outside the area covered by a close lost contact
search by the time it can be effectively started.
(b) When the execution of a close
lost contact search would involve excessive maneuvering
of the ships as a result of their positions
with reference to the datum.
(c) When the submarine’s most dangerous
course can be predicted, or when it is essential
that the units should remain between the
submarine and his target.
(4) BOTTOM SEARCH. When searching
for bottom contacts, an area search should be conducted
with the direction of the search at right angles
to the current.
d. SEARCH TURN. If a zigzag is in use
when a search turn is executed, the zigzag is to
cease automatically and units are to return to base
course. The zigzag is only to be resumed on signal.
While the formation is completing the maneuver,
ships are particularly vulnerable. Individual ships
are therefore to carry out their own torpedo countermeasures
during this time.
e. HELICOPTER MANEUVER DURING
SEARCH TURN. When a ship alters course using a
search turn, helicopters stationed on it are to be repositioned
on the other side of that ship on the new
course.
EXAMPLE
C2D THIS IS A1B
EXECUTE PLAN BLACK OAKTREE
SIGNALS EXECUTE TO FOLLOW
FORMATION YANKEE 090 TACK 40
SPEED 16
A1B
4,000 YD
C2D
DATUM
Figure 9-22. Search Plan 1S Oak Tree
9-87 ORIGINAL