to the axis of the envelope.

Six of these ships were completed in the spring of 1917 and were
quite satisfactory, but owing to the success achieved by the
experimental S.S. Zero it was decided to make this the standard
type of S.S. ship, and with the completion of the sixth the
programme of the S.S.P's was brought to a close.

These ships enjoyed more than, perhaps, was a fair share of
misfortune, one was wrecked on proceeding to its patrol station
and was found to be beyond repair, and another was lost in a
snowstorm in the far north. The remainder, fitted at a later
date with 75 horse-power Rolls Royce engines, proved to be a most
valuable asset to our fleet of small airships.


S.S. ZERO

The original S.S. Zero was built at a south-coast station by Air
Service labour, and to the design of three officers stationed
there. The design of the car shows a radical departure from
anything that had been previously attempted, and as a model an
ordinary boat was taken. In shape it is as nearly streamline as
is practicable, having a keel and ribs of wood with curved
longitudinal members, the strut ends being housed in steel
sockets. The whole frame is braced with piano wire set
diagonally between the struts. The car is floored from end to
end, and the sides are enclosed with 8-ply wood covered with
fabric.