418 
FOREST AND STREAM, 
[Nov. 20 1887. 
are not severe and tbere are no special requirements for re- 
sistance. Alnmimim is therefore STiiTed to Ibeair dncts and 
flttines, and the pipes and cowls, into which forms it can be 
readily made and is easily worked. On the vessel taken for 
the comparison the saving in weight would he about 20 tons, 
with an increase of co«t of only about ?S,000, the cost ratio 
being taken at 1.24. About 3)4 tons are saved in the copper 
and brass cowls, rims and hoods, without increase of cost. 
For the cowls, too, the lighter weight affords greater ease 
of manipulation for trimming to wind. 
(2) For metal doors, wat-er-tight and non-water-tight, the 
advantages of aluminum are in special evidence. For water- 
tight doors the stresses are similar to those of bulkheads, 
the main consideration being stiiTness and resistance to de- 
formation. The distinctive superiority, however, lies in the 
greater ease of opening and closing afforded by the lighter 
weight. On the vessel in question the saving in weight 
would be about eighteen tons and the increase of cost but 
about 16,000. There would be advantage for the substitu- 
tions for some wooden doors, as to staterooms, where light- 
ness is also specially desired. 
(3) For hatches (other than armored), man-hole covers 
and frames, the same considerations hold. The saving in 
weight would be about eleven tons, with an increase in cost 
of about $4,000. 
(4) For torpedo ports and coaling ports, the special advan- 
tage of ease of handling is again in evidence, though the 
conditions of corrosion would require an eft'ective coating on 
the outside. The saving in weiebt would be about five tons 
and the increase of cost about $2,000. 
(5) For dead light, air port, and deck light frames and 
casings, cast aluminum would be well suited, provided due 
attention is given to consideration of corrosion, proper care 
in selection of material of castings, and application of effect- 
ive coating The saving in weight over the brass castings 
would be about fifteen tons without any considerable in- 
crease of cost. 
(6) For metal ladders and gratings, ease of handling due 
to lightness gives a distinct advantage, and conditions of 
corrosion are not severe. The saving of weight would be 
about three tons and increase of cost about $1,000. There 
would also be advantage in many cases in the substitution 
of aluminum for wood gratings. 
(7) For masts and spars the advantage of lightness is in 
special evidence as reducing high weights, and the condi- 
tions of corrosion are not severe. Aluminum is, therefore, 
well adapted for usual service where sails are not carried 
and unusual forces are not to be resisted. It is to be noted, 
however, that in battle an aluminum lower mast would be 
more likely to be shattered and drop its charge of military 
tops, etc. For the lower booms, or boat booms, lightness 
offers additional advantage for rigging in and out. 
The substitution in the case of a vessel carrying two mili- 
tary masts of usual development would be about fourteen 
tons, the increase of cost about $7,000. 
(8) Among additional miscellaneous fittings for the appli- 
cation of aluminum may be mentioned fresh water tanks, 
galley outfit, furniture, ammunition boxes, binnacles, lan- 
terns, etc. 
Reference has been previously made to the fact of alumi- 
num's being largely debarred from boiler and engine appli- 
cation on account of the overthrow of its physical properties 
by heat, even at comparatively low temperature It should 
be pointed out, on the other hand, that this obstacle is not 
incurred in a number of applications in the engine and fire 
rooms, such, for instance, as the parquets or floors, envelopes 
of boilers and condensers, condenser tubes, etc. In connec 
tion with the use for condenser tubes it would be necessary 
to avoid the use of alkalies like soda in cleaning. In the 
above and in many other applications the lightness of alu- 
minum would be in large advantage, particularly for recip- 
rocating parts. In other applications, to parts of machinery 
where unusual forces are not to be feared, where the oft- re- 
peated forces are well known, the high elastic dynamic re- 
sistance would in addition be of decided advantage. For the 
present purpose, however, this field of application is not 
investigated. 
(9) The above applications, assembled, are as follows: 
First, where, at the present stage and under the present 
condition of manufacture, aluminum could be used to ad- 
vantage, provided a suitable alloy other than copper is used, 
and provided due care and attention are given to preserva- 
tion, as follows: 
For Hull Work. 
■ Case of 9,000-ton Vessel > 
Savinff in Weight. Increase in Cost. 
Bulkheads 210 tons. $.57,000 
Casings and trunks 45 tons. 30,000 
Small trunks and ducts....„»,,,j Sitons. 21.000 
Hammock berthing,.......,,.,,,,, ,, 14 tons. 9,C00 
JMetal ceilings..,. 6 tons. 4,000 
Total in hull work.... , 307 tons. $2-31,000 
For Hull Fittings, 
Ventilation system, ducts, pipes, cowls 
andfit ings. ...4. ao tons. $8,000 
Metal doors.....,,.,,....'.,.'...!.,, 4. IStons. 6 000 
Hatches 11 tons, 4,000 
Torpedo ports and coalmg ports 5 tons. 8,000 
Metal ladoers and graiiogs , 3 tons. 1,000 
Masts and spars , 14 tons. 7,000 
Totalfor hull flUings 71 tons. 8 28,000 
Total for hull work .307 tons. 2^1,000 
Total 378 tons. $.4y,000 
Thus, at the present state of manufacture and with pres- 
ent means of preservation, there could be realized with 
safety on a vessel of 9.000 tons a saving of about 380 tons 
with an additional expenditure of about $250,000, or an 
economy of about per cent, of the total weight of vessel 
with about 8}^ per cent, entailed increase of cost. The rela- 
tive advantage Is most marked in the case of hull fittings, 
where the saving of weight is about 14 per cent, of total 
weight of hull fittings, and the entailed increase of cost is 
only about 8)4 per cent, of total cost of hull fittings. 
Second, where aluminum can be used with advantage as 
soon as experiment finds an eflScient coating against corro- 
sion, as follows: 
For Hull Work. 
Case of 9 000 ton Vessel 
Saving in Increase. 
Shell plating. Weight.. in Cost. 
Bottom plaLitig of small vessels 
Bottom plating of la-ge vessels when sheathed 200 tons. 890,000 
Topside platiag of small vessels 
Topside plating of large vessels when not associ- 
ated with armorer armored spaces occupied 
in battle , , . . , , 
Framing. 
Bottom and topside framing for small vessels. . 
Bottom framing except ou er angles of trans- 
verse frames and longiiudinalsin double boc- 
tom and topside framing for large vessels. ,100 tons. 78,000 
Inner bot'om plating 30 tons. 1(5,000 
Decks, plating and beams 235 tons. 165,100 
Total for hull work for sheathed vessel. , .565 Ici'ig.OOO 
Total for hull work for unshe ibed vessel.sea 259,000 
For Hull Fittings. 
Dead lights, air ports and deck light frames atid 
casings - 15 tons. 8 000 
Total for bull work 365 tons. 259,000 
Total 380 Sao9,000 
Thus, as soon as an efficient preservative coat is found, a 
further field will be opened up where with a 9,000-ton vessel 
an additional saving of 380 tons could be realized by an in- 
crease of cost of about $510 000, or a savinef of 'about per 
cent, of total weight and an increase of about S% per cent, 
of total cost. 
When thus occupying its whole legitimate field in hull 
construction, the use of aluminum would realize, in a 9.000- 
ton vessel, a saving of weig>>t of about 760 tons with an en- 
tailed increase of cost of about $510,000, or a saving of about 
8}4 per cent, of total weight with an increase of about 17 
pev cent, of total cost. 
It should be recalled that the above results applv to a 
vessel of war, and for the present purpose it will suffice to 
point out that for a merchant vessel, where conditions of 
battle are not taken account of, the application would be 
larger. 
* * * * -x- * y- * 
(?.— StrMMATrOIT~C0NCLtrSI0NS. 
The above comparisons lead to the following results: 
Comparison for Strength and Weight. 
1. In simple tension, aluminum, -^vhich is about one-third 
as heav^y as steel, has about two-thirds of the ultimate and 
about fourteen- fifteenths of the elastic re=istance. 
In simple compression and shearing the ratios are slightly 
smaller. 
2. In bending, aluminum bars of square section having the 
same weight as steel give about 2 9 times the ultimate 
strength and about 4 .5 times the elastic moment of resist- 
ance, and are about 3 times as stiff. 
Aluminum plates of equal weight give about .5.1 times the 
ultimate and about 7 8 times the elastic moment of resist- 
ance, and are about 9 times as stiff. 
Aluminum shapes of proportioned dimensions of equal 
weight give for I beams about 2 9 times the ultimate and 
about 4.5 times the elastic moment and about 31 times 
the stiffness, and for angles about 2.4 times the ultimate and 
about 3 6 times the elastic moment, and about 3.3 times the 
stiffness. 
3. In elastic eloneration. aluminum gives about 2.S times 
the elongation of steel with a modulus of elasticity of about 
one-third of steel. For elongation beyond the elastic limit, 
aluminum is incomparably below steel, the ratio being 
smaller as the length increases. 
The dynamic resistance of aluminum in tension within 
the elastic limit is. therefore, about 2 6 times the resistance 
of steel per unit of cro.ss section, and is about 7,8 times the 
resistance for equal weight. 
Beyond the elastic limit the dynamic resistance of alumi- 
num cannot be compared with the resistance of steel. 
Convparlson for Cost. 
1. To realize the same resistance, plate work in aluminum 
costs, in general, about 2 8 times as much as steel in hull 
work, and about 1 2 times as much in hull fittings; 
angle work and work in other shapes cost, in general, about 
5 times as much in hull work and about 1.7 times as much 
in hull fittings. 
Cast fittings in aluminum cost about 1.5 times as much as 
in steel, and about the same as in brass. 
In all of these cases the weight for aluminum con.struction 
is less than half the weight for steel, and about one-third the 
weight for brass, 
_ 2. The cost of maintenance and care is at present substan- 
tially greater for aluminum construction than for steel con- 
struction, and increases in proportion to the exposure to 
corrosion, which becomes exaggerated where conditions 
favor galvanic action. 
3. The length of life of aluminum construction under 
favorable conditions must be regarded at present as substan- 
tially shorter than the length of life of steel construction, on 
account of pronounced tendency to corrosion. This tendency 
has been found to be due in most part to galvanic action, 
largely caused by the alloy or impurities in the metal, an 
alloy being necessary to realize good re.sults of strength. Of 
the alloys tried, the copper alloy has given the worst results 
for corrosion. 
As yet a suitable protecting coating has not been found, 
and the field is calling for further .scientific experiment. 
The cases of the employ of aluminum have been unfortu- 
nate in results of corrosion, but they have been incomplete, 
and the conditions, upon examination, have been found to 
have been extremely severe. 
With a properly chosen alloy, like the nickel alloy, and 
with proper care, aluminum can be safely used where there 
is not direct exposure to salt water and spray, and the fur- 
ther extent of the advantageous use to fields where the ex- 
posure is not specially severe is only held back by the lack of 
an efficient protective coating. 
A^OTplicaMons. 
The results of the comparisons for strength and weight 
and for cost lead to the conclusion that at present aluminum 
is adapted for use in hull work for bulkheads, casings and 
trunks, small trunks and ducts, hammock berthing and 
metal ceiling, and for use in hull fittings for parts of ventila- 
tion system, for metal dooi-s, hatches, torpedo ports and 
coaling ports, metal ladders and gratings, masts and .spars; 
this adoption in the case of a 9,000-ton vessel, realizing a 
saving in weight of about 380 tons at an increase of cost of 
about $250,000. 
The same results lead to the conclusion that as soon as an 
efficient coating is found, aluminum will be further adapted 
for the bottom plating of sheathed vessels, for the bottom 
and topside plating of small vessels, part of the topside 
plating of large vessels, for bottom and topside framing of 
small vessels, for topside framing of large vessels, for the 
bottom framing of large vessels, except outer angles in 
double bottom, for inner bottom plating, and deck plating, 
and for dead light, air port and deck light frames and 
casings, realizing by this adoption in a 9,000 ton vessel a 
saving In weight of about 380 tons at an increase of cost of 
about $260,000. 
It is to be remarked that in the above applications it is 
assumed that galvanic action does not set in from the con- 
tact of aluminum and steel, an assumption apparently jus- 
tified by experience thus far; but in course of time it is 
largely probable that appreciable action would set in, if 
some insulating provision were not made in the joints be- 
tween the two metals. It is not believed, however, that 
such in.sulation provision would be impracticable. 
It may be recalled also, as stated in the outset, that per- 
formances and homogeneity of aluminum as taken are some- 
what ahead of the present stage of manufacture, and that 
the applications have been extended to dimensions and scant- 
lings not yet commercially turned out. 
Moreover, it should not be overlooked that the element of 
cost in the maintenance and care of aluminum construction 
and the length of life are not well determined and are diffi- 
cult to evaluate on account of the limited experience. 
The results arrived at are thus to be taken in connection 
with the limitations necessarily imposed by the fact of the 
field being essentially new. 
In summation, and in conclusion, aluminum has incon- 
testable virtues as a structural material. Its great elastic 
elongation and resistance within the elastic limit places it 
far ahead of steel for resisting usual, well determined and 
repeated dynamic forces, while its great comparative light- 
ness marks it for marine construction. On the other hand, 
it has serious defects. An excessively low elongation beyond 
the elastic limit unfits it entirely for use where liable to be 
subjected to violent and unknown dynamic forces; tempera- 
tures beyond atmospheric undermine its physical properties; 
while, notwithstanding au innate superior resistance when 
pure to the attack of corroding agents, the high position on 
the electro-chemical scale causing excessive tendency to gal- 
vanic action, places a severe obstacle in the way of adoption 
where exposed to salt water and spray, particularlv in the 
case of alloys, in which form alone the metal exhibits its 
best physical properties. This last serious defect, however, 
must be considered as subject to constant amelioration with 
increase of knowledge and experiment in precautions and 
higher perfection in manufacture. 
Thus, while this new metal has an important field in ma- 
rine construction, an important field now ready for occupa- 
tion, and additional fields awaiting onlv the improve- 
tnent in conditions for resisting galvanic action, these fields 
are essentially limited, and the larger domains are shut out 
by impassable barriers. 
The early optimist who inferred all virtues from a single 
virtue, and the later reactionist who pronounced general un- 
fitness from a few partial trials, were both wide of the mark. 
The metal is not Utopian, but it has, nevertheless, beyond 
question, an important mission for the serious marine archi- 
tect, who is only waiting further improvement in manufac- 
ture and reduction in cost and further amelioration in con- 
ditions of corrosion. 
For the naval architect of our own country, for our coun- 
try itself, the question has a special significance. 
The maintenance of a strong commissioned naval force 
must be our country's policy for taking its destined part of 
international greatness in regulating the common affairs of 
the planet, but our position and the spirit of the nation 
mark our naval policy specially for a great force kept 
economically in reserve, commissioned only periodically for 
drill purposes. 
In a state of reserve the conditions of corrosion are greatly 
ameliorated. The vessels seek and lie in fresh water; the 
torpedo-boats and small boats, which do not seek fresh water, 
are hauled up under sheds. Under these conditions the 
great obstacle of corrosion is largely removed from alumi- 
num's path. Indeed, aluminum appears to be superior to 
steel in the resistance to the corroding effects of atmospheric 
exposure and of fresh water. 
The question becomes more significant where account is 
taken of the great natural facilities and possibilities of our 
coast line for fresh water basins of large expanse for taking 
vessels of all sizes. It takes on a still more significant aspect 
when It is j-ecognized that nature in the inland routes along 
the coast has marked small craft as our great second line of 
defense; while, in the inland waters of great rivers and great 
lakes m communication with the sea, she has provided im- 
measurable possibilities for the construction and mainten- 
ance of these craft. 
Torpedo boats which are thus marked for a great natural 
economical branch of national defense form now the least 
developed arm of our navy. 
There therefore lies ahead, inevitably, a vast programme 
of torpedo-boat construction, for which every advantage of 
materials of construction shuuld be earnestly sought. For- 
tunately for the nation, this branch of defense admits of 
rapid growth and may be expected to have large expansion 
m the near future. Indeed, the time is not far distant when, 
with treaty restrictions abrogated, we shall see on the Great 
Lakes, vast flotillas of torpedo-boats lying for most of the 
year in economical reserve, free from corrosion. Periodic- 
ally, they will be commissioned for drill purposes, and from 
time to time will sally forth to the .seaboard for mobiliza- 
tion and exercise in the operations of coast defense. 
We would realize thus, at a minimum cost and a mini- 
mum turning away of the nation's energies from the chan- 
nels of production, a great power, tranquil in time of peace 
and good-will, irresistible for defense in time of war. 
[conclusion.] 
Mr. Brand's Challenge. 
From the Yachting World. Nov. S. 
Matters in connection with Mr. ,J. Arthur Brand's chal- 
lenge for the Seawanhaka C. Y. C, challenge cup continue to 
progress, but slowly. On Friday Mr. Brand received a cable 
from his agent, Mr. Sturdee, to the effect that if a race was 
wanted the necessary backing of the challenge by the 
Minima Y. C. would have to be sent immediately. Mr. 
Brand at once placed himself in communication with the 
Minima Y. C, and Admiral Hallowes has been requested to 
call a meeting of the committee to consider the matter. 
Since receiving the cable Mr. Brand has had a letter from 
Mr. Sturdee, informing him that he (Mr. Sturdee) had abso- 
lutely promised the Royal St. Lawrence Y. G. that a British 
boat will be sent over, provided all the arrangements for a 
contest are satisfactory. Mr. Brand is still waiting an 
official communication from the Royal St Lawrence Y. C, 
giving the full conditions for the proposed meeting. 
The 35ft. Knockabouts. 
The second meeting of the Long Island Sound yachtsmen 
interested in the new 25ft. knockabout class was held on 
Nov. 11 at the Grand U nion Hotel. The weather was very 
bad, but a number of yachtsmen turned out, including B. B. 
Crowninshield, of Boston, who was present by request of the 
committee. Mr. Crowninshield's design, which was the 
choice of the first meeting, was finally accepted with some 
modifications, the freeboard, displacement and sail area 
being increased and a bowsprit added. The centerboard 
will be of wood. It is probable that some twenty of the 
yachts will be built. 
The Seawanhaka One-Design Class- 
Through the courtesy of the designer, W. B. Stearns, of 
Marblehead, we are enabled to publish the accompanying 
de.signs of the new 21ft, l.-o^-.l. knockabouts ordered for the 
Seawanhaka Cerlnthian Y. C. Twenty-five of these little 
yachts are now under way at Mr. Stearns' yard. The inte- 
rior plans and further particulars will follow next week. 
YACHTING NEWS NOTES. 
On Saturday, Nov. 27, the annual meeting of the Yacht 
Racing Union of the Great Lakes will be held at Detroit. 
On the following Saturday the annual meeting of the Lake 
Y. R. A. of Lake Ontario will be held at Hamilton. 
Yamija, schr. , R. S. Palmer, from Maderia for New York, 
put into Sc. Thomas on Nov. 5 with foresail carried away, 
sailing again on Nov. 9 after making repairs. The yacht had 
made a long passage, but all were well on board. , 
It is reported, on the authority of the Field, that Valkyrie 
III. will be fitted out for the Mediterranean races by her 
original owners, 
"A regular meeting of the Seawanhaka Cor. Y. C. was held 
on Nov. 9, with Rear-Com. Van Liew in the chair, in the ab- 
sence of Com. Rouse, who has been seriously ill for some 
weeks. The trustees reported the election of fifty nine mem- 
bers, Blling the limit of membership. The race commit- 
tee reported that the contracts had been made with W. B. 
Stearns, of Marblehead, for twenty-five of the new knock- 
abouts. The committee also reported that it had challenged 
for the Seawanhaka cup, and the club, by unanimous vote, 
endorsed the challenge. The Twenty-second street club 
house is now open for the winter, and mess dinners, lectures 
and entertainments will go on as usual. Golf links are novy^ 
Ijelng laid out at Center Island, for use next season, 
