March 4, 1899,] 
FOREST aND stream. 
two and four-cycle motor, there is no question but that 
theoretically the four-cycle has the preference, the supe- 
riority claimed consisting, first, that the motor requires 
a charge only every other stroke; secondly, that between 
each working stroke there takes place a thorough clear- 
ing of the cylinder, so that when the charge of gas enters 
there remains no part or trace of the burnt gases from 
the last charge, which it is claimed, and quite rightly, 
' weakens the new charge. Now, with the two-cycle 
motor, which has an impulse of the piston each revolu- 
tion, part of the fresh gas escapes with the exliaust of the 
burnt gas in the operation of expelling the old charge, 
and there is, notwithstanding, more or less of the burnt 
gas that remains to weaken the fresh charge. On the 
other hand, having an impulse at each revolution, the 
area of the cylinder does not have to be as great; there- 
fore there is not so much gas required to make a charge. 
There being an impulse each revolution, the diameter and 
weight of fly-wheel is also much less in this type, as it 
has no idle revolution to OA^-ercome, which in turn takes 
less power to maintain the desired speed or momentum. 
Taking it all in all, a saving of a few cents per day should 
hardly be taken into consideration in any launch motor, 
the cost of operation being so small in any case, and 
most certainly not to be considered in comparison with 
the first cost. 
Danger of Naphtha. — The question is often asked, 
Why is naphtha, gasolene or in fact any of the hydro- 
carbon oil so dangerous ; and if so, how is it the use of 
these oils is steadily increasing? There are many liquids 
in common daily use that are equally as dangerous, if 
not more so, but as we have from long use become ac- 
customed to handling them with a knowledge of their 
properties, we do not give them a thought. 
To begin with, the first thing is to impress th6 irovice 
in the use of Iwdro-carbons that it is not the liquid that is 
to be feared, but the gas formed by evaporation charg- 
ing the air with a highly explosive mixture. 
Likewise, few people know that, unlike many other 
gases in common use, the gas thus formed is heavier 
than the atmosnhere; therefore will not rise, and for 
that reason does not as readily disperse itself, and will 
remain in a dangerous state in places and receptacles 
long after expected. 
A tankful of gasolene can be set on fire and will, of 
course, burn fiercely, like all oil. but will not explode. 
Take this same tank, however, and put in a small quan- 
tity and disturb it so that the air in the tank will become 
charged, and j^ou will have a highly explosive mixture. 
We have often heard people remark that they feared a 
large tank full of naphtha, where it should be the empty 
one to be afraid of. 
The gas formed by the mixture of air and naphtha is 
explosive with from twelve to forty-five parts of air to 
naphtha, thirty-three being about its most explosive 
point; below twelve and above forty-five the gas will 
burn, but not explode. Naphtha and gasolene are alike, 
except that many vary a few degrees in their test; but in 
most cases what is called gasolene is generally of a grade 
somewhat lighter and more volatile than the grades of 
naphtha in common use. 
Steam and Electric Motors. — The steam engine has 
been so completely supplanted by the various naphtha 
and gasolene motors that it is hardly a factor to be con- 
sidered as a power for anything but large yachts or very 
high speed launches, and therefore does not come under 
the scope of this book. 
There is no question nor doubt but that the electric 
motor is the ideal launch power, but as yet they are in a 
very crude state, and are dependent on an independent 
plant to recharge their storage batteries, which at the 
best will only run at full sped for a comparativeljr short 
time, to say nothing of the great weight of the batteries 
that it is necessary to carry. They are in use by some 
of the large steam yachts as tenders, but in their present 
state of development are unsuited to common use. 
Naphtha, Alco and Ammonia Motors. — There are 
also What are commonly called "naphtha motors," 
which, with the alco and ammonia vapor motors, should 
properly be classed with the steam engine, as by these 
sj'stems the naphtha, alcohol or ammonia is Jirought to 
a boiling point in a retort or boiler by means of a naph- 
tha, kerosene or other oil fire, the results being that, the 
fuel in the retort generates steam or gas which is ad- 
" mitted to an engine of varying form, and after passing 
through the engine is then condensed and returned to the 
retort, the principles of these motors being identical with 
the ordinary steam engine. 
Propellers. — Next we come to the propeller and the 
means of reversing the same. Although any motor of 
the two-C5rcle type can be fitted to reverse, it is not so 
with the four-cycle. Owing to motors having no power 
to speak of on a start from a standstill, and for-other 
reasons, it has been found by far the best plan to keep 
them running the one way, and to reverse either by means 
of gearing, friction clutch, or reversing the blades of the 
propeller. The first-named deivice is mostly to be found 
on motors of the four-cycle type, the builders of the two- 
cycle mostly all using the reversible bladed propeller. 
The geared and friction reversing mechanism is made in 
many dift'erent forms, but in fact the principle is really 
identical in all and includes only simple, well-known me- 
chanical movements. The reversible bladed wheel con- 
sists of a hub, into which the blades are fastened so that 
by means of a sleeve surrounding the shaft and fastened 
to an idler, which engages an arm or bearing point on 
the blade, causes the blade to turn on its axis in the hub. 
The sleeve revolves with the shaft and is moved back- 
ward and forward by means of a lever located in most 
cases near or on the motor, although it can be ari-anged 
to work from any part of the boat. These reversing 
wheels are mostly very simple, strong and effective, and 
we think they are the ideal reversing method for all 
kinds of" motors. They should, however, be made in all 
their parts' of best hard bronze. While on the subject, 
it may be said that it is almost always a surprise to the 
novice .in motor construction at the smallness of diam- 
eter of the wheels used on them. This is owing to the 
fact that it has been found to give better results to make 
the wheels small and increase thereby the revolutions of 
the motors, adding power to the motor and lessening 
the vibration. 
Choice of Motors. — We will now suppose you are 
in the market for a motor, or a launch ready equipped. 
and, as in many cases, you are undecided as to the make 
of motor you will select. 
Points in Construction. — Now, what are the points 
in construction you should consider? To begin with, 
by all means buy of a reliable firm, and as near your 
home as possible, for no rhatter how well or carefully it 
is made, there is always the liability of a break-down or 
repairs , on account of wear. Look over the working 
drawings of the makers and insist that they shall show 
sufficient thickness of the cylinder to allow of its being 
rebored at least twice without its being too thin for 
safety. There should be a clearance space of one-third 
of the length of the stroke between the piston when it 
is on the upper center and the top of cylinder. The con- 
necting rod should be, from center of the wrist-pin to 
center of the crank-pin, not less than twice the length 
of the stroke. The crank-shaft should be of forged steel 
(not cast) of good diameter, and the crank-pin should 
be of the same diameter as the crank-shaft. All bearings 
should be of hard bronze and as long as possible, re- 
rnembcring always that length of bearing does not in- 
• crease friction. Be sure your motor is supplied with 
good grease and oil cups, and that the cylinder is fitted 
with a sight-feed lubricator that will feed heavy oil in 
cold weather without at first having to heat the lubri- 
cator to start it feeding. See that all parts of the vapo- 
rizer are of brass or bronze, and that all connections be- 
tween the motor and wheel are of the same metal, ex- 
cepting where the reversing is done by gears or clutches, 
in which case these parts will have to be made of cast 
iron or steel. Your motor should be run in the shop 
at least twenty hours on a belt and by its own power 
before you attempt to use it, as it is a great annoyance 
to attempt to break in a new motor, especially in a 
small boat. In buying a motor, it is like buying a suit 
of clothes; that is to say, if you want to get a first class 
article, you must pay a first class price, and we advise 
you in any case to either get the best or none at all. 
Study the catalogues, and when you find any one offering 
you something as good as the best at half price, be sure 
that it is, and then look for the list of extras — that gen- 
erally explains matters. Do not let a few pounds in 
weight rr an inch or two in height influence you, as in 
many casis what would be good serviceable motors are 
ruined by being built down too close. 
The America Cup. 
The- work on- the new cutter for the trial races is now 
progressing steadily at Bristol, and in spite of the efforts 
of the builders to maintain the most rigid secrecy, a great 
deal is already known about her. The "guessing con- 
test" is a good deal easier than in the case of Defender 
foirr years ago, -as the latter yacht was a very wide de- 
parture, both in design and .construction, from her prede- 
cessors, Navahoe, Vigilant and Colonia. In the present 
case it was practica'ly a foregone conclusion at the out- 
set that any new go-footer would be but an improvement 
in detail on Defender, and the guessing was limited to 
the exact dimensions and the material for the plating. 
The latter seems to be finally settled in favor of Tobin 
bronze instead of manganese bronze for the bottom, and 
nickel steel instead of aluminum for the top sides, as well 
as for the deck beams and 'some other of the upper struc- 
tural members. 
The most exact and reliable information thus far pub- 
lished is the following, by W. E. Robinson, in the Boston 
Globe of Feb. 27. It is, of course, not official, and we are 
not aware of the sources of Mr. Robinson's information, 
but we have sufficient confidence in his reliabihty and his 
technical knowledge to reprint it in the Forest and 
Stream as the best information yet made public. 
Whether or not, the new America Cup defender, now 
building by the Herreshoffs at Bristol for Com. J. Pier- 
pont Morgan and C; Oliver Iselin;- will- be faster than 
Defender of '95 is the most interesting yachting question 
at the present time. The question as to whether or not 
the chosen American defender will beat Shamrock will 
come up later. It is for an answer to the first question 
that information about the new boat has been so eagerly 
sought. 
The Globe has from time to time given its readers the 
best possible information it could obtain in this direction. 
It now supplements it with dmensions and details of con- 
struction, which leave no doubt as to the manner and type 
of boat the new defender w'ill be, and which enables the 
prediction to be safely made that she -will be many min- 
utes faster than Defender on almost every point of sail- 
ing and' under almost every condition of racing wind and 
weather. 
A few mistakes have been made in previous information, 
but in general the new boat has been outlined as an im- 
proved and more powerful Defender, and not as any 
radical departure from a type known to be fast, able and 
seaworthy. This conclusion is fully borne out by the addi- 
tional information now given. The new boat is an im- 
proved Defender, with more power and sail, and yet with 
practically just as easj' a form to drive and with all the 
lines for speed that made the champion of '95 a marvel. 
She will also be more lightly and yet more thoroughly 
built than Defender. Aluminum h,as been entirelj- dis- 
carded in her construction, and yet because of more care- 
ful attention to detail the absence of this lightest of all 
metals will not be missed. 
The Globe has in its possession sufficient information 
to show not only these points, but also many others which 
would support and confirm them. Yet while it desires to 
give its readers all possible information, for an answer to 
the question as to the boaf s speed, it by no means desires 
to give information of wdiich the designer of Shamrock 
could take advantage to Herreshoff's disadvantage. Cer- 
tain important things, such as the exact weight of the 
lead keel, the placing of the mast and the general idea of 
the sail plan are therefore withheld, as are also exact di- 
mensions. These are important things to a designer, and 
with them he would have his opponent's boat to a cer- 
tainty. 
It is not the same with matters of construction, now that 
Shamrock is well under way. Designer Fife is not likely 
to modifj' his construction plans from anything he might 
learn from this side of the water. The Globe therefore 
gives the new boat very fully in this direction, for in it is 
shown her lightness and strength as compared with De- 
fender. General dihiensions are only approximately 
given, and no attempt is made to give her lines to an inch 
or do more than to show what she will look hke and 
wherein she will differ from Defender. 
The new defender is 130ft. over all, 90ft. waterline, just 
over 24ft. beam and not over 20ft. draft, although very 
close to that figure. Defender was some 5 or 6ft. shorter 
over all, 89ft. waterline, and just over 23ft. beam. Her 
draft was close to 20ft. The new boat's keel plate, stem 
and sternpost are of cast bronze, the frames and deck 
beams of nickel steel, and her plating of Tobin bronze up 
to the waterline and nickel steel above. Defender was 
plated with manganese bronze below the water line and 
alummum above. Most of her deck beams were of 
aluminum. A lead keel of 90 tons is sufticlently approxi- 
mate for the purpose of this article. 
In model the new boat is a nearer approach to the out- 
and-out fin keel type, as shown in the Herreshoff 30- 
footers, than was Defender. Wetted surface is cut to the 
last inch on the new boat, while the lead is carried lower, 
the body is made rounder and more powerful, and the 
whole form made easier to drive at high speed. Quick- 
ness in stays is also an improvement over Defender, al- 
though the latter whirled very quickly. The lead keel is 
shorter and deeper, and its form better for easy motion 
through the water. 
Like Defender, the new boat is of the fin keel type in 
great cutting away of the forefoot and in having her lead 
keel bulbed. Also, like Defender's her frames start from 
the keel plate on top of the lead keel, and although giving 
largely the effect and appearance of a plate fin. still retain 
the usual form of construction, The rudder is also hung 
on the stern post, and is not a balanced one clear of the 
fin, as in the smaller boats. In brief, the boats are close 
to fin keels in design, but not in construction. 
Compared with Defender's the new boat's midship sec- 
tion shows a 'sharper hollow at the turn from the keel' 
into the body of the boat, a flatter floor and a rounder 
side, with about ift. more beam. These differences in 
themselves show a more powerful and easily driven boat, 
as well as one that should be faster in reaching or down 
the wind. A faster reaching boat is what Mr. Iselin is 
confidently expecting, while it is a matter of record that 
Defender was not much faster in spinaker work than Vig- 
ilant. 
The sheer plan of the new boat shows a forefoot very 
much more cut away than Defender's, while the lateral 
plane is improved by having the keel straight on the bot- 
tom instead of "rockered." The rake of the sternpost 
is about the same in both boats — 45 degrees. 
The lead keel of the new boat is close to 3cft. long on 
top, where Defender's was 35. At its heel it is 6ft. deep, 
while forward, just before its bottom line turns upward, 
it is 7ft. 6in. From the heel forward the bottom of the 
keel is flat for about 20ft. The line then rounds upward 
in an easy curve to a straight line of about 5ft. on the for- 
ward end. The top of the keel , is a straight line, but it 
is about lyik. higher forward' tWan it is aft. The bot- 
tom of the keel is parallel with the waterline. 
The top of the lead keel is 2oin. wide at about a third 
of its length from the forward erud. It rounds to a point 
forward and tapers to a width of 4in. at the after end. 
The widest portion of the keel is close to the bottom 
below the Avidest portion on top, and here the lead is 
34in. through. The bottom is flat, and there is only a 
very small round up at the edges. The line of the section 
of the lead keel at its thickest part shows only a very 
slight inward curve as it eroes upward to the top. In 
fact, the lead keel might well be described as a plate rather 
than a bulb, having its upper edge 2oin. wide and its 
lower 34, with the corners slightly rounded. The fore 
and aft sweep of the lines of the lead is a very easy one, 
and the keel is much easier to drive through the water 
than the ordinary bulb. 
Defender's lead keel was not so deep as this, was 
rounded up fore and aft and was decidedly bulbed. The 
greatest thickness of lead was not so low down as in the 
new boat, and hence not quite so. effective for power for 
carrying sail. The new boat shows much the same im- 
provement as in the ,46-footer Wasp over the famous 
Gloriana. 
From the lead keel the stem of the new boat rises a 
few feet in an easy outward curve, and then takes almost 
a straight line to the waterline and a little beyond, when 
it again rises by an easy inward curve to meet the line of 
the deck. Defender's stem showed a curve on the long 
sweep upward that was about as much outside of a 
straight line as the new boat's is inside, and the resem- 
blance of the new boat to the 30-footers is therefore all 
the more striking. 
The new boat's overhang forward is longer than De- 
fender's, and the upward turn of the stem from the water- 
line is therefore not so sharp. 
The rudder of the new boat is set well under her and 
will run to the bottom of the lead. The after end of the 
lead has a groove molded in it to fit the round of the rud- 
der post. 
In construction, the new boat is on the same general 
plan as Defender, but has lighter plating, and much varia- ' 
tion in the sizes of the frames and beams are heaviest 
amidships and grow smaller toward the ends of the boat. 
There are also improvements in details over Defender. 
The new boat's keel plate is of cast bronze, Hin. in 
thickness, and having flanges on the edges 4in. in height. 
Cross webs of the same height are placed every 2oin. on 
the plate, to which the floors and frames are riveted. 
Plate, flanges and webs are cast as one piece, so that the 
practical thickness of the plate is 4J^in. 
The plate was cast in three sections for convenience in 
•casting. Both ends of the inner section and the inner 
ends of the other section have flanges 2j'2in. deep on the 
bottom, and these, as well;a's the upper flanges, are riv- 
eted together, making the piate practically a solid one, 30ft. 
long, 4j^in. deep and 2oin. wide at its widest portion, 
tapering to a point forward and to a width of about 4in. 
aft. Slots are cut across the top of the lead keel to admit 
-the lower flanges where the sections are joined, so that 
the plate lies close to the lead for its whole length. 
The lead keel is fastened to the keel plate by bronze 
large screws, g}^'ni. long and lin. through. The screws 
have hexagonal heads, for which a special wrench is 
needed to screw them into the lead. There- are two of 
these screws for every -space in the keel plate, and they 
