Year: 1868

4 Mr.. John Elder, Of the celebrated ship


builders firm, Randolph, Elder 81 Co., in
Glasgow, has recently patented q most
original form on lr0n-ciad ram for coast de-
fenses and attacks On sea fortihcations
Mr.. Elders vessel is formed below the
water line as a segment Of an enormous
sphere, say 25 feet deep and 200 feet in
diameter, Of the cirealaE waterline, This
corresponds to n small piece of sphere, of
which the versine over q CHORD of 200 feet
Is p feet long Over the water line the
armo--elad sides are short truncated cone,
and in the center OF this circular deck high
castle OF tower, carrying three or tour tiers
OF guns, is arranged This vessel, being


perfectly circular ID plan, has neither bow
nor stern, nor any of the other steering at
tributes of ships now i'm existence; it bears,
in fact, the same relation of outline and
form to the ordinary ships as the form Of a
crab bears 20 that Of fish. The power Of
locomotion Is given to this craft by the re-


action propeller. The reaction wheel


probably Mr. Randolph's improved water


leF propeller-is placed 10 the center of the


vessel, at the lowest point Of the spherical


segment, and the election Of water can be
effected through four openings placed at


four equi- distant points in the circumfer-


ence, 50 as to command the direction Of


propulsion without any steering arrange


ment, BY forcing the water through one or


two Of the passages which command any one


OF the four quadrants inclosed BY them.


There are, however, steering or DETECTION


boards fitted to the end Of the passages


through which the water il elected and, by


using these boards a rotary motion can be


given to the crab BY ejecting the water


from two opposite passages simultaneously,


and placing the steering boards into a cor


responding position, the total engine power


of the vessel can be made available for


setting the ship into a revolving movement


round its own vertical axis. The velocity


which the ship is capable of attaining under


these conditions, measured at the outer
circumference, is very great, since there is
no other resistance to this motion except
the skin-friction. Mr.. Elder proposes to
make use of the great momentum which
this high velocity OF movement will afford
for rammlDg purposes. The whole circular
edge Of his vessel which is of sharp angle
in section, represents, so to say, the edge of
circular saw or revolving disk wheel, and
the accumulated momentum Of the rotary
movement can be used for producing a
destructive effect upon the sides of any
vessel with which this revolving turret ship
would come into contact The circular form
allows Of very large stowage room as COM
pared with the ordinary form of ships, and
it produces a base of such stability as to
allow the erection Of tower of great hight
in the center, so as to obtain better facilities
for attacking objects on shore Mr.. Elder
has carried out some experiments as to the
resistance to propulsion in straight line
offered by his form Of vessel compared with
the ordinary forms. He made two models
representing equal tunnage, one of the
Black Prince shape and the other of his
spherical form, and the resistance Of these
two models was measured by an apparatus
which afforded a simple mode Of comparing
the relative proportions Of these resistances.
The result was only about 10 per cent in
favor Of the Black Prince model, and this
seems TO Indicate that the new vessel would
be capable Of attaining a fair speed under
steam. The advantages offered by this form
are Of different kinds, the most prominent
being maximum Of internal accommodation
or stowage room, with a minimum of ex-
posed surface. a circular OF turretshaped
armored side, and an extraordinary facility
of maneuYTing in an action; last, but not
least, the total absence of any exposed
points of weakness, or Achilles heels, -
such as most iron-clads at present possess.
Engineering.