436

NICHOLAS'S SEAMANSHIP AND NAUTICAL KNOWLEDGE

Fig. 16.

Side Bar Keel.

Figure 17 (i) and (n) show how a centre line keelson is attached
to its neighbouring members. The centre through plate A is stiffened
on its upper edge by the two continuous angles B, the horizontal flanges
of which provide a rivet connection to the reversed frames and the lug
pieces marked d. The lower edge of the keelson plate is connected to
the keel plate by means of the two angles k> and to the floors by means

Fig. 17.
of short vertical angles marked a. In Figure 17 (ii) a foundation plate
D is shown, and the angles at Jc are continuous, the frames being cut
to admit of this, but in Figure 17 (i) the frames are continuous and pass
^through notches cut in the lower edge of the keelson plate, the angles kt
in this case, being fitted in short lengths between the floors.
Stringers.—Above the turn of the bilge there is a "stringer," similar
in construction to a keelson. These longitudinals are named stringers
when they are attached to the frames, and keelsons when attached
to the floors. They have similar functions, both contribute longi-
tudinal strength, and help to stiffen the shell plating by keeping the
frames and floors in their correct relative positions so that they all
act together.
The hold stringer in Figure 13 is formed by a narrow plate which is
notched round each frame, the outer edge of the plate touching the shell
plating to which it is riveted by means of short chock angles fitted
intercostally between the frames. The inner edge of the stringer plate
Is stiffened with a continuous angle on its under side, the vertical