Year: 1879

lifting gear is brought over tho wreck.
This lifting gear consists Of couple Of
pontoons, connected together By hollow
deck, and fitted with screw engines, cen
triiugal pumps and winding gear, and
having controlling air chambers on the TOP.
This forms a wreck-lifting apparatus as
well as an ordinary dry dock structure.


The lifting gear having been brought
over the wreck, the booms are then parted,
and one Is moored to each side OF the lift
ing gear. The end Of the steeI-wire ropes
from the toggles are then passed up sopa-
rately through distinct hawse pipes in the
deck above. The end Of each rope is
made fast to winch-barrel, which Is ca
pable Of independent action, and is other.
wise SO arranged as to insure uniformity
Of strain being brought on all the ropes.
The wire-ropes are made fast at the top Of
the tide, and the winches are revolved 50
as to get fair strain on during the fall Of
the tide. At the same time water ~ ad-
mltted into the pontoons forming the bot
tom Of the dock until they are sunk nearly
to the under side Of the deck. At dead
low tide the pontoons are pumped free Of
their contained water, and the vertical lift
obtained is equal to the rise Of the tide
plus any extra buoyancy which may exist
between the depth to which the dock was
originally submerged and its greater power
Of fotation than the weight Of the wreck.
The vertical lift having been accomplished,
the dock will steam 10 shore carrying the
wreck with It until the latter grounds.
The pontoons will again be filed with
water, and the wire ropes wound in as far
as possible Pumping out win then take
place, and another feet in shore woald hs


made. These operations would be repeat
ed as often as necessary, and, after tho


first, would be Independent Of the state of
the tide. By this means the wreck would


thus be speedily brought into shallow


water, and made sufficiently water tight to


enable her to be foated and received into


the floating dock which, in another chas.


aeter, had assisted in rescuing her from


immersion In modified form Of the


gear for boring and making attachments,


the tube is only about Is inches in diam
eter, and is used as fulcrum for carrying


the boring gear, the operations being


watched from above by the aid Of refract-


ing mirrors.


, We thus have an ingenious system OF


ship raising propounded, in which the risk


Of the outlay is confined to very small


proportion of the plant--namely, the tow
er, and its gear--and to the labor. Should
f the raising Of the wreck be rendered i'm.


possible by any unforeseen Circumstance


the dock would still be perfectly capable


of being used as dry dock The total


cost of such dock, capable Of lifting
/, /, weights up to 10000 tons, is stated to be
,, about 100000. The expenses Of making
! tower, taking it out, and proving the pos


sibility or otherwise Of making On attach


ment, is estimated at e2000. Seeing th,
number of wrecks which are strewn arounc
, our coast, It is, at least, question for con-
sideration whether a trial could not b.
! made with this apparatus, the principles q
: which are based on considerable expert
ence of Surprising. II would appear Il
/ be more desirable, seeing that if the lift
!, ing plant failed to effect its Object,
! could at once be used as an ordinary DR.
! dock.