Figure 1-71.—Blueprint title block (A) Naval Ship’s Systems Command; (B) Naval Facilities Engineering Command.
Some companies use odd numbers for right-hand parts
and even numbers for left-hand parts.
Drawing Lines
The lines used in working drawings are more than
a means of showing a picture of an object for the
purpose of building or repairing. The way a line is
drawn has a definite meaning.
Thick lines are used for the visible outline of the
object being drawn. Medium lines are used for the
dotted lines representing hidden features and for
cutting-plane,
short-break,
adjacent-part,
and
alternate-position lines. Center lines, dimension lines,
long-break lines, ditto lines, extension lines, and
section lines are represented by thin lines.
To understand blueprint reading, you must know
the different types of lines used in general drawing
practice and the information conveyed by each. Some
of the lines of major importance are illustrated in
figures 1-72-A and 1 -72-B. The correct uses are
illustrated in figure 1-73.
Blueprints make it possible to understand, in a
comparatively small space, what is to be made or
repaired. Of the many types of blueprints you will
use aboard ship, the simplest one is the plan view.
‘his type of blueprint shows the position, location,
and use of the various parts of the ship; for example,
to find the battle stations, sickbay, barbershop, or
other parts of the ship.
In addition to plan views,
other blueprints, called assembly prints, unit or
subassembly prints, and detail prints, show various
kinds of machinery and mechanical equipment.
Assembly prints show the various parts of the
mechanism, how the parts fit together, and their
relation to each other. Subassembly prints show the
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