e up of three longitudinal lobes, one
above and two below, which when viewed end on gives it a trefoil
appearance. The internal rigging is attached to the ridges formed on
either side of the upper lobe, where it meets the two side lobes. From
here it forms a V, when viewed cross sectionally, converging at he
ridge formed by the two lobes on the underside of the envelope which is
known as the lower ridge.

To the whole length of the top ridges are attached the internal rigging
girdles and also the lacing girdles to which are secured the top and
side curtains. These curtains are composed of ordinary unproofed
fabric and their object is to make the envelope keep its trilobe shape.
They do not, however, divide the ship into separate gas compartments.
The rigging girdle consists of a number of fabric scallops through
which run strands of Italian hemp. These strands, of which there are a
large number, are led towards the bottom ridge, where they are drawn
together and secured to a rigging sector. To these sectors the main
external rigging cables are attached. The diagram shows better than
any description this rigging system.

Ten main suspensions are incorporated in the Coastal envelope, of which
three take the handling guys, the remaining seven support the weight of
the car.

The horizontal fins with the elevator flaps, and the vertical fin with
the rudder flap, are fixed to the ridges of the envelope.

The car was evolved in the first instance by cutting away the tail
portion of two Avro seaplane fuselages and joining the forward portions
end on, the resulting car, therefore, had engines at either end with
seating accommodation for four. The landing chassis were altered,
single skids being substituted for the wider landing chassis employed
in the seaplane. The car consists of four longerons with struts
vertical and cross, and stiffened with vertical and cross bracing
wires. The sides are covered with fabric and the flooring and fairing
on the top of the car are composed of three-ply wood. In the later
cars five seats were provided to enable a second officer to be carried.

The engines are mounted on bearers at each end of the car, and the
petrol and oil tanks were originally placed adjoining the engines in
the car. At a later date various methods of carrying the petrol tanks
were adopted, in some cases they were slung from the envelope and in
others mounted on bearers above the engines.

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