The Iowa Class Battleships were the only BB's to get a Mk 48 computer. This happened during the Korean War. The Mk 48 simplified the shore bombardment problem, because it did a lot of the work for you.
Computer Mk 48 Mod 1 operates in conjunction
with the gun order computer,
stable element, and director to provide
an accurate solution to the problem of
shore bombardment by indirect fire. It
is designed to operate with the main and
secondary batteries of cruisers and
battleships, and may be used with antiaircraft
or surface fire directors and
computers or range keepers.
Computer Mk 48 Mod 1 primarily is
designed to solve a fire control problem
by using a visible reference point to direct
fire at an obscured target whose map location
with respect to the reference point is
known. This computer translates
data that describe reference point position
with respect to the ship into data that
describe actual target position with respect
to the ship. The figure below shows the data flow
for direct and for indirect fire control. The data that describe target position with
respect to the ship then are transmitted to
the gun order computer for computation
of firing data.
In indirect fire, Computer Mk 48 Mod 1
computes the quantities involved in target
location by combining three sets of data:
Location of the reference point with
respect to the ship.
The reference point, at which the director is continuously
aimed, is located by its relative bearing, range and height.
Location of the target with respect to
the reference point. This is
established by X-Y map coordinates,
reference point height,
and target height.
Level and cross level referenced to
the target line-of-sight.
By combining these three sets of data,
Computer Mk 48 Mod 1 furnishes to the
gun order computer the following quantities:
Offset relative target bearing,
(director train to target),
Target slant range and
In addition to transmitting target data
to the gun order computer, Computer
Mk 48 Mod 1 transmits data to the gun
director to keep it aimed at the reference
The Table of Contents in the downloaded file is hyper-linked for each section. Just click on the section you want to go to the first page of that section.
This file is also indexed and searchable. Enter the phrase you want in your reader's search block. If that does not work, try a different phrase.
OP-2074 Part 1 Pages 1-151 22.8 mb
OP-2074 Part 2 Pages 152-303 17.6 mb
back to table of contents Page 1
Related Material: The Stable Element
These files require the free Adobe reader or browser add in to view. If you cannot open these files, you can download and install the free reader. Be sure to select the version for your operating system. (Windows Vista, XP, Mac, Linux, etc.)
Get free Adobe Reader if you can't open files