June 13, 1896.] 
block of wood, but which fails to cover such a complicated 
form as a yacht. 
In the case of the simpler forms made up of plane or 
fiat surfaces, the projection of the various straight lines 
forming the edges is not a very difficult matter, but with 
a solid bounded by curved surfaces, such as a yacht, this 
primitive method is inadequate. There are few positive 
lines, perhaps even none at all, but only the unbroken 
surface. Every surface, however, is made up of an in- 
finite number of small points, and if we can lay off a 
certain |number of these points and locate them on the 
sides of the surrounding box we shall have a satisfactory 
representation of the object. Referring to Fig. 12, the 
point A, one of the corners of the solid, is located by six 
separate measurements, one from each side of the sur- 
rounding box, as Af from the bottom, Aa from the top, 
Ad' from the left side, etc, Now it is evident that if we 
FIG. IS. 
have the distance Af above the bottom of the box the 
height of A is positively located and the measurement Aa 
useless. Similarly the point is located laterally by the 
distance Ad', from the left side of the box, and the dis- 
tance Aa' is useless. We may then discard entirely three 
sides of the box, the top, the front end toward the drafts- 
man and the right side. This is actually done in ortho- 
graphic projection, the object to be drawn is considered 
as situated in the angle between three planes, one below 
it, one at the left side and one at the back, as in Fig. 14. 
The point P is assumed to be suspended in space in a 
position with reference to the bottom which is measured 
by the line P A, through the point and perpendicular to 
or at right angles with the lower plane. Its distance 
from the side plane is measured by another perpendicular, 
P C, to that plane, and from the rear or end plane by the 
distance P B. It is evident that no further measurements 
are necessary, but the point is fully and definitely lo- 
cated. 
Now we may drop entirely our simile of a box and 
adopt the terms of descriptive geometry, as used by every 
draftsman. The three sides which we have retained are 
known as the coordinate planes, planes of reference, or 
planes of projection; the object being referred to them or 
projected or thrown upon tnem. The perpendicular to a 
plane of projection through any point, as P A, is called a 
projecting line, and the foot of this line, where it inter- 
sects the plane, as at A, is called the projection of the 
point on the given plane. In Fig. 15 we have the same 
point, P, and also two others, Q and B. It is evident that 
any two points must mark the end of some straight line, 
and any three points must be on some line, straight or 
curved. As we have already seen, a, plane, as the term is 
FIG 16. 
applied in descriptive geometry, is merely a flat surface, 
such as the three planes of j rejection, originally the sides 
of our glass box. The simplest conception of a plane is 
that of a sheet of glass of indefinite extent, through which 
everything is visible. In Fig. 15 the points, Q, P, R, are 
assumed to be each equally distant from the bottom and 
side planes, and consequently they mark a straight line, 
QPR, The projections of the points on the lower plane, 
q, p, r, must also mark a straight line, parallel to the side 
plane. Now, if we imagine a plane to pass through the 
line QPR and perpendicular to the lower plane of projpc- 
tion, the three projecting lines, Qq, Rr, and Ss, will also 
lie in this plane. The line of intersection of this new 
plane with the lower plane of projection, q, p, r, will be 
the proj action of the original fine, QPR. This fine of in- 
tersection of an auxiliary plane with one of the planes of 
projection is called the trace of the plane; and, similarly, if 
the line Q P R be continued until it intersects the end plane 
at S, the point S is called the trace of the line. The ver- 
tical line S3 is also the trace of the auxiliary plane on the 
end plane. 
These auxiliary planes are of the utmost importance in 
marine drafting. In the drawing of buildings or 
machinery there are many prominent and definite lines 
and angles which may be directly projected upon one or 
another of the planes of projection, but a vessel offers 
little save an unbroken curved surface, devoid of all lines. 
It is by the application of these imaginary planes to this 
surface that the draftsman is enabled to cut from it any 
lines which he may require, just as they might be cut 
from the wooden model with a saw. If it were desirable 
to obtain from a wooden block model the various water- 
lines, it would only be necessary to adjust the model on 
the table of a circular saw and to cut it into a number of 
slices of the requisite thickness, from each of which the 
outline of a waterline could be drawn direct on the paper. 
FOREST AND STREAM. 
This process, in fact, is very commonly followed in work- 
ing from a wooden model, the model being made of a 
number of thin pieces of board, called lifts, united by 
screws; when the model is completed the screws are re- 
moved, the lifts separated and the outline of each drawn 
on paper. By this process the model is practically de- 
stroyed in order to obtain anyone set of lines; it might be 
glued up again and sawn transversely instead of longitudi- 
nally to obtain the lines that make up the body plan, but 
FIG 17. 
it would then be past all use and another model would be 
necessary to obtain the section lines and diagonals. This 
same process of sawing into sections and marking the 
outline of each can be done even more readily and accu- 
rately by the use of auxiliary planes on the drawing than 
by actually sawing up the wooden model, and it is essen- 
tial that the young designer should become thoroughly 
familiar with the projection of points and lines and the 
passing of planes through them. 
In Fig. 10 is shown a curved line, RSTUV, lying par- 
allel to the lower plane and with its concave side 
toward the side plane. Being thus parallel to the lower 
plane, its projections on the side and end planes are neces- 
FIG 18 
sarily straight lines, as rV. The projection on the lower 
plane is a curved line passing through the feet of all the 
different projecting lines, Rr, Ss, Tt, Uu, Vv. 
In Fig. 17 the same curved line is shown, at the same 
distance from the side plane; but inclined at an angle, 
a'r'a, to the horizontal plane. The horizontal projection 
of the line will now be R s t u v, a different curve, the 
distances Rr', Ss', etc., still being the same; but the dis- 
tances measured along the side plane being shorter, as rV 
is shorter than r's', etc. To obtain the horizontal projec- 
tion of the line in its true form, a process termed rabatting 
is employed. This is merely the revolving or hinging of 
the original plane in which the line lines, indicated by its 
traces, r'a', a'b', about some line as an axis until it takes 
e - 
i 
SIDE ELEVATION 
END ELEVATION 
£ < 
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V 
* 
GROUND PLA N 
f 
FIG. 19. 
the position shown in Fig. 16, parallel to the lower plane. 
We will conceive of the plane r'a', a'b', as revolving about 
the line Rr' until it reaches the position r'ab, each point of 
the line, as S, describing an arc of a circle about the line 
Rr'. Each point on the line is now in the same position as 
in Fig. 16, and may be projected directly on the horizon- 
tal plane, giving the points S' T' U' V, the broken line 
through them and R' being the required true horizontal 
projection of the line. 
In Fig. 18 we have the original block, its sides lying 
parallel to the planes of projection, as in Fig. 11. In all 
of the figures, from 11 to 18, it has been necessary to show 
the three planes and the various objects in perspective, 
in order that the reader might see them as he would such 
481 
a model as is sometimes constructed of cardboard and 
threads in order to illustrate the subject. Our aim, how- 
ever, is not perspective, but plain orthographic projection 
such as is employed by the marine draftsman. In Fig. 18 
the solid block is shown, with its three projections on the 
different planes. Let us now assume that the block itself 
is removed entirely and the three planes of projection are 
so folded back as to present a single plane surface instead 
of an angle. This will give us Fig, 19, the ordinary draw- 
ing of the machinist, architect or designer. 
The horizontal plane, once the botttom of our glass box, 
and on which is projected the bottom of the object, is 
called the ground plan in ordinary mechanical and archi- 
tectural drawing, but is known to the designer as the 
half -breadth plan, its various lines showing the breadths 
of one of the two symmetrical halves of the Vessel. The 
drawing above it, once the left side of the box, is the side 
elevation, or in designing the sheer plan, as it shows the 
sheer or line of the top of rail or deck, the contour of 
stem, keel, stern and rudder, and the centerboard if there 
be one. The drawing on the right, the rear end of the 
box, is the end elevation,, or to the designer the body plan, 
and it shows the transverse sections of the yacht, equiva- 
lent to the ribs. As will appear later, the front end of 
the box is used indirectly; and in some cases, as in the 
roof plan in an architectural drawing, and in fact the 
deck plan in a yacht, it may be assumed that the projec- 
tion is made upward on the top instead of downward on 
the bottom of the glass box; but even though other planes 
of projection may be used at times for special reasons, it 
is sufficient for the draftsman, and far simpler, to con- 
sider only the three thus far described. 
The 15ft. Class. 
Evert day brings news of new boats for the 15ft. class, and there 
can be no question that a most interesting fleet of these little flyers 
will shortly be afloat. The main question now is how soon will the 
majority of them be ready, and how many will show up at the line by 
June 22, but two weeks off. Nearly all of the boats are intended for 
the trial races of the Seawanhaka C. Y. C, but it is quite evident that 
many of them, if nominally ready, will still be very far from com- 
plete or in fair racing trim. Among those now on the stocks is one at 
Bay Ridge, built by some of Mumnrs boatbuilders from the design of 
Chas. Olmstead, designer of Trilby, a fln-keel of similar model, 5ft. 
6in. beam; the hull is single-skinned with smooth lap planking, and 
the deck is canvased. Over at Communipaw A. Hansen has on the 
stocks a 15-f ooter from their own designs for the Ball brothers, who 
sailed Ethelwynn last year. She will be of the skipjack variety, with 
sloop rig. 
No prize has yet been offered for the worst freak in the class, but 
such a contest might be exciting, even if not instructive or otherwise 
useful, as there are at least two boats on the stocks which will be in 
every way eligible to compete. One of these is building by T. W. 
Webber, of New Rochelle, for Hazen Morse; and the] other for T. 
F. Day, of The Rudder, was designed bv the Crosby Catboat and 
Yacht Building Co., of Fifty-sixth street, Bay Ridge. Both of 
these boats embody the same idea, of a double hull, or more 
properly of two boats in one, the lower one for measure- 
ment and the upper one for actual sailing. The Crosby boat 
is 24ft. over all by about 6tt. beam, the midship section being 
a V of rather more depth than in most of this class. The stern- 
post is well under the boat and is plumb; from the heel the keel 
rounds down and then up forward to the waterline, from which it 
turns sharply and runs along parallel with the water and an inch or 
two above it. The designed length on waterline is to be 10ft., which 
will allow a sail plan of 400sq. ft. The midship section is a fair and 
continuous line from rabbet to planksheer, but the sheer plan presents 
the appearance of a boat 10ft. over all, with plumb sternpost and a 
deeply immersed rudder; on top of this boat being another 23ft. over 
all, and with a very slight rocker to the keel. The boat will have a 
wooden centerboard of the old style. It is proposed to have her trim 
so that with the required weight of 3001bs. of lead aboard to represent 
the crew she will measure but 10ft. on the waterline; but with the reg- 
ular crew and the boat under way she will in reality sail on a very 
much greater length and possess the power of a 20-footer, carrying 
the same sail plan. JuBt how all this is to happen we do not under- 
stand, and we see saveral practical difficulties in the way. However, 
the success of the experiment will soon be put to a practical test . 
Still another 15-f ooter is building at Bergen Point by Mr. Walter Brown 
for his brother, W. F. Brown, owner of Crocodile, from a model by 
Philip Elsworth. 
In addition to Mr. Morse's boat, Webber is building another for a 
member of the Westchester Country Club. 
Mr. Clapham, at Roslyn, has two more under way: one of the barn- 
door type, for a member of the New York C. C, and another, an im- 
proved Imp, for« member of the New York Y. C. 
American Model Y. C. 
BROOKLYN— NEW YORK BAY. 
Saturday, May 30. 
The opening races of the American Model Y. C. from off the new 
salt-water station was somewhat marred by the few starters and a 
half a day lost in measuring all the 17 yachts that proposed to start, 
but did not come to time. The new measuring tank not being in 
proper condition for accurate measurements, only approximate meas- 
urements were taken by measurer Nichols, who will have to go 
through the same performance when the tank is properly adjusted. 
Four yachts came to the line for the first class. A great deal was 
expected of the Ripple, but owing to her peculiar steering gear she 
could not keep up with the other yachts down wind, they using the 
ordinary automatic steering gear. She finally gave up racing for the 
day. Mary Alida was unfortunate after finishing the first heat out- 
side the flags by getting away from her owner and running under the 
nosepole of a large sloop yacht lying at anchor, making a complete 
wreck of her mast and rigging, therefore not being able to start in 
the other heat^ 
The third class resolved itself into a very pretty race between 
Minerva and Ida May, Minerva eventually winning after a stubborn 
fight. 
The second class did not nil, the rules calling for three yachts or no 
race, and only two showing up, the same being the case with the 
schooner class. 
A S.W. to W. wind blew all day, fluctuating from 3 to 6 miles per 
hour, with a moderate sea on. 
FIRST HEAT— FIRST CLASS SLOOPS. 
Start. Elapsed. Corrected. 
Mary Alida, Job. Brown 1 51 25 Outside. 
Kittle D., H. V. Davis 1 50 18 0 16 15 0 16 43}^ 
Ripple, L. R. Thurlow 1 51 03 Did not finish. 
Edith, Neff & Pigort 1 49 20 0 14 00 0 13 29]^ 
Henrietta, J. D. Casey 1 51 10 Fouled. 
SECOND HEAT. 
Kittie D 2 19 02 - 0 16 33 0 17 51J^ 
Edith 2 17 26 0 15 14 0 14 4S^| 
Henrietta 2 17 17 0 17 15 0 15 20J4 
FIRST HEAT — THIRD CLASS SLOOPS. 
Minerva, J. D. Casey 3 23 40 0 22 00 0 23 39 
Dolce, E Autenen 3 24 55 Did not finish. 
Ida May, Neff & Pigott 3 24 51 Did not finish. 
SECOND HEAT. 
Minerva 3 57 28 0 15 17 0 15 16 
Dolce 3 57 33 Outside. 
Ida May 3 56 50 0 13 43 0 14 16 
THIRD HEAT. 
Minerva , 4 21 05 0 12 43 0 12 42 
Ida May 4 20 38 0 13 05 0 13 05 
Edith wins in first class sloops, first heat, by 3m. 14s. ; second heat 
and race by 38J^s. 
Minerva wins in third class sloops, first heat, by walkover; third 
heat and race by 23s. 
Cape Cod Y. C. 
EAST DENNIS— BARN3TABLE BAY. 
Saturday, June B. 
The first race of the Cape Cod Y. C, on Jane 6, was sailed over two 
rounds of the five-mile course, the times being: 
Length. Elapsed. Corrected. 
Addie, R Nickerson , 25 04 2 10 25 1 38 37 
City of Chicago, F. Crosby 25 06 2 15 11 1 43 18 
Eclipse, H. H. Sears 25 09 2 15 00 1 43 51 
Judges— P. M. Crewell J. W. Smalley, D. Shiverick. 
