Nov. 30, 1897.] 
FOREST AND STREAM. 
: 417 
SEAWANHAKA ONE-DESIGN KNOCKABOUT. 
bottom plating where the conditions of corrosion are not 
severe, due regard being taken to the conditions of the un- 
derside and the difficulty of access. With a coating of fair 
eflBciency, and with due attention, aluminum offers decided 
advantages for general adoption for inner bottoms. Taking 
the case of a 9,000-ton vessel, the gain in weight with plates 
of equal stiffness would be about 30 tons, and the increase in 
cost would be about $16,000. 
4. AdaptaMlity for bulkheads. 
The integrity of bulkheads is undermined as a rule by dis- 
tortion destroying water-tightness, while rarely, if ever, is 
the metal called upon to exert its ultimate strength of resist- 
ance. The superior stiffness and greater elastic resistance of 
aluminum mark it, therefore, for special adaptability for 
bulkhead purposes, for both plating and stiffeners. 
Standing vertically, as it does with ease of access, and 
without exposure of any kind, the conditions for preventing 
corrosion are peculiarly favorable. 
Aluminum therefore, is eminently suitable for bulkhead 
purposes for all classes of vessels. 
Taking a vessel of 9,000 tons of unusual subdivision and 
high freeboard, and assuming equal stiffness, the saving of 
weight and increase of cost are about as follows: 
Weighc Increased 
Saved. Cost. 
Transverse bulkheads below pro'ective deck 45 tons. 833,000 
Transverse bulkheads above protective deck, 
W. T 30 tons. 27,000 
Transverse bulkheads above protective deck, 
light divisional 7 tons. 5,000 
Longitudinal bulkheads below protective deck. . .96 tons. 77,000 
Longitudinal bulkheads above protective deck. . .23 tons. 18,000 
Longitudinal bulkheads above protective deck, 
light divisional 9 tons. 2 000 
210 $157,000 
Total weight saved 210 tons, about 2J^ per cent, displacement. 
Total increase of cost $157,000, about 5 per cent, of total cost. 
5. Adaptability for decks. 
For reasons pointed out above, aluminum is debarred from 
association with the protective deck. The nature of its re- 
sistance, however, is suitable for other decks, both for beams 
and plating, exception betng made for stringers and tie- 
plates, reservation being made also for considerations of 
fragments and splinters in battle as pointed out above. 
For beams, however, with the present conditions of manu- 
facture, the sizes required for large vessels, for which there 
has yet been no demand, could probably be produced only 
with increased difficulty, though for the present purpose it 
will be assumed that they could be produced at the price 
quoted above for shapes. 
Conditions of corrosion would exclude the use for the 
upper deck unless the plating were covered by wood flat. 
As a matter of fact such a wood flat is found, as a rule, on 
the upper deck of war vessels where the deck is of steel. All 
other decks would require efficient linoleum or other cover- 
ing on top and an efficient coating on underside. For 
structural purposes the .deck stringers would remain of 
steel. 
For a vessel of 9,000 tons, supposing the decks except the 
protective deck to be of aluminum, both plating and beams, 
the saving of weight and increase of cost, assuming equal 
stiffness, would be about as follows: 
Weight Increased 
Saved. Cost. 
Main deck about 85 tons. about $60,000 
Gun deck.. ...about 60 tons. about 43,000 
Berth deck about 67 tons. about 47,000 
Platform deck about 21 tons. about 15.000 
Flats and floors about 2 tons. about 1,000 
235 $165,000 
Total weight saved about 235 tons, about 2% per cent, of total 
weight. 
Total increase of cost about $;65,001), about 5)4 per cent, of total 
cost. 
6. Adaptability for other hull work. 
(1) For casings and trunks the same advantageous con- 
ditions are offered for aluminum as pointed out in the case 
of bulkheads. For a 9,000-ton vessel the saving in weight 
would be about 45 tons, about .51 per cent, of the weight in 
steel, with an increase of cost of about $30,000, about 2X 
times the cost in steel. 
(2) For small trunks and ducts, coaling trunks, ventilator 
trunks, forced draft ducts, ammunition hoist trunks, chain 
lockers, blower casings, the same conditions hold; the sav- 
ing in weight would be about 32 tons, and the increase in 
cost about $21,000, bearing about the same ratios to tota 
weight and cost in steel as found for casings and trunks. 
(3) Similarly for hammock berthing where the saving in; 
weight would be about 14 tons, and the increase in cost 
about $9,000, bearing about the same ratios to total weight 
and cost in steel. . 
II' (4) For metal ceilings inside the same conditions hold, 
giving a saving of about 6 tons with an increase of cost of 
about $4,000, bearing about the same ratios to total weight 
and cost in steel. 
It should be remarked that the greater conductivity of 
aluminum would increase the condensation, requiring 
special provision against same in living spaces. 
7. Adaptability for hull fittings. 
(1) For the ventilating system the conditions for corrosion 
