gs, 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; Zeppelin
at this time used a plain light rubber-proofed fabric, but this was not
considered suitable for a ship which was required to be moored in the
open, as in wet weather the material would get saturated and
water-logged. Various experiments were carried out with cotton, silk
and ramie, and, as a result, silk treated with Ioco was finally
selected. This cover was laced with cords to the girder work, and
cover-strips rendered the whole impervious to wet. Fire-proofed fabric
was fitted in wake of the gondolas for safety from the heat of the
engines.

Two gondolas, each comprising a control compartment and engine-room,
were suspended from the main framework of the hull. They were shaped to
afford the least resistance possible to the air, and were made of
Honduras mahogany, three-ply where the ballast tanks occurred, and
two-ply elsewhere. The plies were sewn together with copper wire. The
gondolas were designed to have sufficient strength to withstand the
strain of alighting on the water. They were suspended from the hull by
wooden struts streamline in shape, and fitted with internal steel-wire
ropes; additional wire suspensions were also fitted to distribute the
load over a greater length of the ship. The engines were carried in
the gondolas on four hollow wooden struts, also fitted internally with
wire. The wires were intended to support the gondolas in the event of
the struts being broken in making a heavy landing.

Two engines were mounted, one in each gondola, the type used being the
8-cylinder vertical water-cooled Wolseley developing a horse-power of
160. The forward engine drove two wing propellers through the medium
of bevel gearing, while the after engine drove a single large propeller
aft through 4 gear box to reduce the propeller revolutions to half that
of the engine. The estimated speed of the ship was calculated to be 42
miles per hour, petrol was carried in tanks, fitted in the keel, and
the water ballast tanks were placed close to the keel and connected
together by means of a pipe.

No. 1 was completed in May, 1911. She had been built at Barrow in a
shed erected on the edge of Cavendish Dock. Arrangements were made
that she should be towed out of the shed to test her