TAKING UP MINES.
Mines should be raised in the reverse order from that in which they
were planted if the conditions of wind and tide are favorable. With
a cross tide or a strong cross wind, the mines should be taken up in
regular order from one side so that the planter will not drift onto the
mine field.
A yawl or launch takes position at the outer mine on each side. The
mine-buoy rope is hauled up taut in order to locate the exact position
of the mine. The boat holds fast until directed from the planter to let
go. While the anchor and mine are being taken aboard the planter, the
boat remains off the bow to render assistance if necessary.
The distribution box is raised by underrunning the multiple cable, or
by means of its raising rope if the buoy has not been removed. The box
is taken aboard the distribution box boat, the lid is removed, and the
mine cables, in turn, disconnected from the multiple cable. The planter
passes close to the distribution box boat. A heaving line which has
been made fast to the outer mine cable is thrown to the bow of the
planter. If this should fail, a man throws a heaving line from the bow
of the planter. If the conditions be unfavorable for passing a heaving
line, a launch may carry the line to the planter. The heaving line
attached to the cable is hauled aboard and the cable placed over the
cathead. The planter then proceeds to underrun the cable. If the water
be shallow, the cable is carried through a snatchblock to the aft deck
and coiled, or it may be carried to a cable-reel forward. If the water
be deep, or the cable can not be raised easily by hand, it is carried
through a snatchblock to the drum of a hoisting windlass and coiled
as before mentioned. (If placed on a cable-reel, the ends should be
insulated and tagged. Mine cables Nos. 1 to 9 should be placed on one
reel and Nos. 10 to 19 on another, both reels being carefully marked.)
When the raising rope is reached, it is carried with the cable over the
cathead. The bight of the rope is hauled in quickly, carried through a
snatchblock, and a few turns taken on the drum of a hoisting windlass.
The rope is untied from the cable as soon as possible. If there be
danger of losing the rope, it should be made fast at once. The anchor
is raised until within a few feet of the cathead. It is lifted aboard
by means of the boom, or by the differential block on the anchor davit.
At the same time a man is sent over the side of the planter near the
mine davit (a rope ladder may be used) to secure the hook of the
differential block in the sling attached to the maneuvering ring of
the mine when it comes to the surface. To bring the mine to the proper
place to accomplish this, a man should be ready to secure the mine-buoy
rope with a boathook; other men should be ready to pull the mine
forward, if necessary, by means of the cable. The mine is raised by
the differential block of the mine davit. It may be raised by the boom
and fall; or by means of a tackle secured to the mine davit, the end
of the rope running through a snatchblock to the drum of a windlass.
The distance weight of the automatic anchor may be raised by the fall
of the boom, or by an improvised tackle. An eye should be made in the
distance rope for this purpose.
If the end of the cable is lost, the work may proceed as follows: The
planter moves out to the mine if its buoy is still in place. A sling
made of raising rope may be thrown over the mine, or two raising
ropes are tied together and one end is passed to a launch which moves
around the mine and brings the end back to the planter. Both ends are
placed over the cathead, through a snatchblock, and around the drum
of a hoisting windlass. The mine is hoisted, bail up, until near the
cathead. It can then be transferred to the anchor davit. The mine cable
is pulled in until the raising rope is reached. The work then proceeds
as before. If the mine buoy has been removed, a yawl may drag for the
cable with a grappling iron. If the raising rope should break or be
lost, the mine may be raised as mentioned above, except that the mine
must be transferred to the fall of the boom and the anchor raised by
means of its mooring rope, or the mine may be transferred to the anchor
davit, as before, and a raising rope made fast to the mooring rope of
the anchor and carried over the cathead, through a snatchblock, to a
hoisting windlass. The mine, as soon as the strain is taken up by the
raising rope, is unshackled. The anchor is then taken aboard in the
usual manner.
As soon as the mines are taken aboard they are disconnected, the
ropes are coiled, and all matériel placed so as not to interfere with
subsequent work. As soon as the matériel is unloaded on the wharf it
should be cleaned thoroughly and stored.
If the multiple cable is to be left down, the ends of the conductors
are insulated, the lid replaced, and the box lowered by means of a
raising rope, the end of which is made fast to the bight of the bowline
of the anchor rope.
If the multiple cable is to be taken up, the end is passed to the
planter, run through a large snatchblock on the bow, and coiled on a
cable-reel as it is raised. Whenever a multiple cable is coiled on a
reel it should be secured so that both ends will be available for test
when the cable is stored.
=Unloading mines.=—Should any of the mines be loaded with dynamite
the utmost care must be exercised in unloading them. (See p. 76.)
Some contrivance must be rigged up so that the first few turns of the
compound plug may be accomplished by the operator at a distance, as
there is great liability of explosion, due to leakage of nitroglycerin
into the screw threads. After the compound plug is removed the
precautions to be observed are given in Appendix No. 1.
Should the mine be loaded with guncotton or trotol, no danger is to
be apprehended in unloading; the usual precautions in handling high
explosives must, of course, be observed.