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 bags, and hand-operated valves on the top of a few
bags for control purposes. Nets were laced to the framework to
prevent the bags bulging through the girders.

The whole exterior of the hull was fitted with an outer cover;