Figure 3-14. Stuffing box adjustment, hull numbers 8500
thru 8519 and 8520 thru 85S9.
sight, which for all practical purposes is a true line. This
method consists of boring a large hole in the ends of two
boards. One board is fitted at each end bearing of the set
Figure 3-13. Sea water strainer insured when the
to be aligned. A small hole (about 1/16-to 1/8-inch) is
coupling bolts are secured.
drilled in two pieces of thin sheet metal. The sheet metal
is placed on the boards and the small holes are adjusted
Methods of Determining Alignment.
so that they are aligned with the center of the end
bearings. A light is placed behind the board on one end
(1) Running a line wire. The proper location of the
and observed through the hole in the board at the other
bearings on main propulsion shafting may be checked by
end. The intermediate boards are adjusted so that the
running a line wire. This consists of rigging supports just
light can be seen through all the holes. The center of
clear of the end of the outer bearings of the set to be
these holes serves to establish the reference line.
aligned. A length of piano wire is stretched between the
supports. The supports must be rigid and not subject to
(3) Flange method. When it is suspected that the shaft is
deflection when the wire is put under tension. The wire
out of alignment, it should be checked by slacking the
should be attached to the supports in such a way that it
coupling bolts at a coupling near the suspected area on
can be accurately centered in the end bearings. After the
the shaft. Feelers are inserted between the coupling
wire has been centered in the end bearings, the wire
flanges, and if there is a greater distance between the
forms the line of reference (when corrected for sag) for
faces at one part of the coupling than at another, the
all the intervening bearings.
shafts are out of alignment at these places.
(2) Optical method. Alignment of shafting by the
optical method makes use of the ,line of