wed the
external shape. The girders were secured to a steel nose-piece at the
bow and a pointed stern-piece aft. These girders, built of duralumin
sections, were additionally braced wherever the greatest weights
occurred. To support these girders in a thwartship direction a series
of transverse frames were placed at 12 feet 6 inches centres throughout
the length of the ship, and formed, when viewed cross-sectionally, a
universal polygon of twelve sides. For bracing purposes mesh wiring
stiffened each bay longitudinally, so formed by the junction of the
running girder and the transverse frames, while the transverse frames
between the gasbags were stiffened with radial wiring which formed
structure similar to a wheel with its spokes. The frames where the
gondolas occurred were strengthened to take the addition weight, while
the longitudinals were also stiffened at the bow and stern.

Communication was provided between the gondolas by means of an external
keel which was suspended from extra keel longitudinals. In this design
the keel was provided for accommodation purposes only, and in no way
increased the structural stability of the ship as in No. 9 and later
ships. This keel, triangular in section, widened out amidships to form
a space for a cabin and the wireless compartment. The fins and
rudders, which were adopted, were based entirely on submarine
experience, and the Zeppelin method was ignored. The fins were fitted
at the stern of the ship only, and comprised port and starboard
horizontal fins, which followed approximately the shape of the hull,
and an upper and lower vertical fin. Attached to these fins were box
rudders and elevators, instead of the balanced rudders first proposed.
Auxiliary rudders were also fitted in case of a breakdown of the main
steering gear abaft the after gondola. Elevators and rudders were
controlled from the forward gondola and the auxiliary rudders from the
after gondola.

The gasbags were seventeen in number and were twelve-sided in section,
giving approximately a volume of 663,000 cubic feet when completely
full. Continental fabric, as in use on the Zeppelin airships, was
adopted, although the original intention was to use gold-beater's skin,
but this was abandoned owing to shortage of material. These bags were
fitted with the Parseval type of valve, which is situated at the top,
contrary to the current Zeppelin practice, which had automatic valves
at the bottom of the ba