he horns of the mine itself
could reach the sides of the ship. It also cut the mooring and enabled
the mine to rise to the surface and be destroyed by gun-fire.

[Illustration: A PARAVANE

Hoisting in the starboard paravane of the P.V. mine-defence gear.

_Topical Press_]

In order to understand this appliance it is first necessary to know what
is the action of the majority of moored mines on coming in contact with
a ship. It seldom happens that a vessel strikes a mine dead on the bow
or stem-post. The cushion and dislocation of water formed by a big and
fast ship around its bows is usually sufficient to cause the mine to
swing a few inches away from the bow and to return and strike the ship
several feet back on the port or starboard side. A careful study of Fig.
30 will show how this is prevented by the deflecting wires of the
paravane.

The paravanes themselves are submerged torpedo-shaped bodies which hold
the wires under the surface and away from the ship's side, deriving
their ability to do this from the speed at which they are being towed,
submerged, by the ship itself. A piece of string through the axle hole
of a small wheel, which is then placed on the ground and pulled along,
will give a good idea of the action of the paravane against the passing
water.

It is not possible to give here the exact details of this highly
ingenious device upon which so much scientific and practical attention
was wisely bestowed, but sufficient has been said to enable the reader
to form a clear conception of how the mine was caught and held away from
the ship's side by the deflecting wire of the paravane.

This device, in one of its many forms, was fitted not only to warships,
but also to many hundreds of merchantmen, and was known to have
saved thousands of tons of valuable shipping and cargo.

[Illustration: FIG. 30.--Plan showing the chief characteristics of the
paravane mine defence gear. _A._ The bow of the ship. _B._ The paravanes
being towed submerged at an outward angle. These appliances maintain a
fixed depth below the surface and hold the ends of the deflecting wires
_C_ well away from the ship's sides. _C._ The submerged deflecting
wires, held at one end by a short projection from the ship's stem-post
below the water-line, and at the outer end by the submerged paravanes.
_D._ A mine and its mooring caught by the deflecting wires and held away
from the ship. In such a case it would slide down the deflecting wire