Analysis
Part 1: Primary Distinguishing Characteristics
The primary identifiable features in the piece of wreckage are
the two gun tubs, the gallery structure attached to either side
of them, and the landing light array attached to one of the gun
tubs. In order to identify the ship, we need to positively identify
these items.
Gun Tubs
Japanese warships were notable for the variety of projecting platforms
that typically festooned their sides and superstructure. These
platforms were used to mount a wide variety of equipment, including
spotting glasses, fire-control directors, radio aerials, and guns.
However, the sheer size of the wreckage platforms (approximately
14 feet in diameter) rules out Type 95 directors and minor equipment
such as spotting glasses. Furthermore, a 14-foot wide tub is too
small to be a platform for either a dual 120mm or 127mm gun mount.
Heavy AA guns of this type were typically mounted on individual
platforms which were around 21 feet in diameter, and were supported
by much heavier central support columns. However, 14 feet closely
matches the size of dual 25mm anti-aircraft gun mounts (as taken
from scale drawings of Japanese warships of the period). Furthermore,
the fact that these tubs were part of a gallery structure (i.e.
a grouping of gun tubs connected by walkways) indicates that the
tubs were for 25mm mounts, since heavier weapons tended not be
part of a contiguous gallery structure, but were sponsoned out
individually from the ship. For all of these reasons, the evidence
strongly indicates that the wreckage platforms are dual 25mm gun
tubs.
Bulkhead Structure
Despite the top-down (or more accurately, bottom-up) nature of
the underwater photographs of the wreckage, some basic characteristics
of the bulkhead to which the platforms are attached can be made
out:
1.
The bulkhead is from a relatively flat-sided portion of the
ship.
2. While the gallery structure between the gun
tubs has been largely crushed by the distortion of the object,
there do not appear to have been any major structures in this
area.
3. From undersea video footage shot of the object,
a porthole can clearly be seen. This porthole is not visible
in the top-down photo mosaics, but is to be found on the extreme
right-hand portion of the bulkhead structure, approximately
five feet away from the support structure of the right-hand
gun tub. |
Primary Identification
Characteristics
The remainder of the ship identification process centers around
finding a ship that matches the wreckage. This means finding a portion
of a ship that meets all six of the following criteria:
1.
A large portion of a 25 mm machine gun gallery,
2. Attached to a flat portion of the ship,
3. With a porthole located about five feet from
one of the gun platform support struts.
4. Where two of the 25mm tubs are adjacent to
each other, without intervening fire-control equipment or
other platforms between them
5. And where the gallery structure continues on
either side of the tubs for at least 7-8 feet in each direction,
6. And where one of the gun tubs has a landing
light array attached to the outermost point of the tub. |
From
these six requirements, a positive identification of the ship
can be reached.
|
Figure 11: Landing light array, with red lines denoting major structural
members. Note asymmetric shape. Dotted lines indicate probable position
of three missing landing lights. The wires at the end were rigged
fore and aft and were used to stow the array.
Landing
Light Arrays
The wreckage attached to the left-hand gun tub closely matches
a Japanese landing light array, despite having been crumpled
by its impact with the seabed. Identification features include:
1.
The structure is roughly a right triangle in shape, which
indicates that it is not the lower portion of a radio
aerial. Aerials were more symmetric in nature, and can
be thought of as being a very long, skinny pyramid.
2. Radio aerials appear to have been composed
of lighter gauge steel (which makes sense for a rather
long object that must be able to be lowered in and out
of a horizontal position by a relatively small motor).
By way of contrast, the main bar of the wreckage on the
bottom is rather heavy looking. The fact that this bar
also has holes drilled in it indicates that this
particular protrusion needed substantial structural strength
(and hence was composed of heavy gauge steel), but that
the builders were also concerned with the overall weight
of the structure. This usage of perforations in main weight-bearing
members to reduce topweight is typical of Japanese naval
construction.
3. Radio aerials were much larger (30-40 feet
in length) than the 12-14 foot long object attached to
the gun tub. The object appears to be unbroken, and ends
cleanly at its terminus (except for trailing wires). A
radio aerial, since it is composed of several long structural
members, would be expected to break less cleanly in the
midpoint of its length if it had been torn in half here.
4. The presence of the white rectangular object
on the upper part of the arm closely matches the size
and shape of one of the landing lights. The positions
of the other three lights are indicated on the annotated
diagram of this piece of wreckage. |
In summary,
this piece of wreckage is a landing light array, and not a radio
aerial or some other type of antennae. |
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