432	NICHOLLS S  SEAMANSHIP  AND  NAUTICAL  KNOWLEDGE
ally and transversely to withstand all the normal stresses to be expected
when the ship is labouring at sea with her cargo intelligently distributed
and securely stowed.
The longitudinal framing consists principally of keel, stem and
stern posts, keelsons, bottom longitudinals, margin plates, stringers.
The transverse framing consists of floors, frames and sometimes reversed
frames, tank side brackets, beams, beam knees and pillars. The shell,
inner bottom and deck plating also add considerably to the strength of the
ship and form the most important part of the structure, not merely
because they are vital to her flotation but because the plating is the
heaviest iten^ of all the components.
We shall now discuss these several members of the ship.
•4
A TRANSVERSE SECTION.
Figure 13 shows a few frame sections at the midship part of a sailing
ship, or of any Vessel fitted with open floors. It has been drawn to
give us an opportunity of introducing to ourselves the names of the
several components of the structure and their particular functions.
First, note the "bar" keel secured to the hull by means of the "garboard"
strakes; these are the two strakes next to, and on each side of, the keel.
The garboard strakes are "flanged" or bent down to fit against the keel
to which they are riveted, and they provide the only connection between
the keel and the hull.
The Frames extend from the upper deck to the keel and, in earlier
types £fships, a "reversed" frame was riveted to the frame so that the
two angle bars when riveted back to back formed a very rigid rib.
T?he reversed frame in our figure is separated from the frame angle at
the turn of the bilge at the floor head, and is carried along the top edge
* of the "floor" to which it is riveted, whilst the frame bar is riveted to
its lower edge thus stiffening very effectively both edges of the floor
plate.
The "Floors" are the vertical plates extending from bilge to bilge
between the inner and outer bottoms. Sailing ships had no inner
bottom plating riveted to the top of the floors, just planks laid fore and
aft, some of them portable so that the spaces between the floors, named
the "limbers," could be cleaned and dried up. a very important operation
prior to loading cargo.
Beams.—The top ends of the port and starboard frames are tied
together by means of a beam, the beam being efficiently connected to