The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1871-08-09

CoMPosITE SHIPs,-The idea of employing iron
frames and wooden pankiug in the construction
of vessels has been tried for some time in Eng
land, and, offers advantages over the use of wood
or iron alone. By the employment of iron and
wood together, it was intended that the peculiar
disadvantages of the iron ship, namely, the ten
dency of the bottom to foul, should be avoided
by applying copper sheathing, and, at the same
time, the great structural strength of the iron re-
tanned. The composite plan also facilitates div-
sion of the hull, by water-tight bulkheads, in
compartments, thus adding immensely to the
safety of the vessel A recent writer on the sub
iect, in the Mechanics 1fdgdsine, says :" An
iron ship is locally weak but structurally strong
while the converse is the case with woodruff
Ship. An iron ship can be built with any desired
number of water-tight compartments, whereby al
the cost of some Inconvenience in internal ar
engagements. largely-increased degree of safety
for crew, ship and cargo can be attained. They
are also less costly than wooden ships, and they
are, in addition, more durable. The points Of
advantage which are by some considered inner
ent so to speak, in a timber-built ship, are too
well known to need reorganization here. There
is of course, less general strength of hull in wood
en- than in iron ships, but then the former pos
ses1 ehe important advantage of having their bot
toms sheathed with metal-an advantage of no
triaing nature In fact, the chief objection to
iron ships is the rapid fouling of their bottoms.
This difficulty once efectually overcome, wooden
ships would soon become curiosities of naval ar
chitecture. When the composite principle of
ship construction first came into fashion, it was
generally believed that they would, as the system
became more perfected, displace alike ships built
entirely of iron and those built entirely of wood
Prima facie, the system appeared to combine in
itself all the advantages and some others in adj
dition, belonging to both iron and wooden ships,
and varied an ingenious we're the methods of COM
bnation and construction adopted. 1t was con
tended in favor of the composite ship that her
framework of iron permitted other being built in
compartments, if thought necessary, while her
wooden bottom could be sheathed with metal.
The same facilities exist in composite as in iron
ships for the construction of these bulkheads,
and it is only necessary for any person, however
unacquainted with the art Of shipbuilding, to re-
feet upon the numerous known instances of ships
sinking after collisions. to recognize the impor-
lance of supplying every composite ship with
this undoubted means of safety. 1t is, in fact,
calamity of very frequent occurrence, and at the
present time, when so much is being said, though
little, we fear, done-with the view to increased
safety and comfort on board our merchant and
this point upon the attention of all who are en-
gagged in the designing of ships for our mercan-
tile navy. There have been several instances of
ships provided with these forward or collision
coming end on in violent collision,
and still remaining afoat and getting safely into
port"
The galvanic action which took place when
other than copper bolts were employed to fasten
the copper sheathing and the wooden planking to
the iron frames, has necessitated the abandon
ment, to a great extent, of the composite prin-
ciple. The cost of copper bolts is excessive, and
those of galvanized iron are not suited to the pur
pose. A really seaworthy, well-built ship is,
however, only produced at great expense, whether
it be constructed of wood, iron or on the compo-
site plan, and the additional expense of copper
bolts would add prOportionally less to the ex-
pense than to the durability, safety, and sailing
qualities of the ship. Engineering and Mining
Journal