816 
FOREST AND STREAM; 
[Dec. 26, 1903. 
cessive reports of the yacht racing associations of Great 
Britain and with the very learned and elaborate articles 
of other English, German, Danish and French writers, 
I cannot but think that the subject has received scien- 
tific treatment; in fact, I believe a perusal and careful 
study of the records of the last measurement committee 
of the New York Y. C. will convince anyone that a con- 
sistent attempt has been made by that club to arrive at 
the scientific principles involved in the problem and 
that the work of that committee has resulted in the 
formulating of a rule that is founded on correct prin- 
ciples. N, D. Lawton. 
New York City, Dec. 21. 
Editor Forest and Stream: 
In compliance with your request, I send some com- 
ments on the interesting article of Mr. Charles Lane 
Poor on yacht measurement in Forest and Stream 
of Nov. 21. 
It is a convincing exposition of some of the funda- 
mental fallacies of the current type of rules. There is 
little novelty in the substance of Mr. Poor's criticisms; 
but they are notably clear and are valuable. He has 
developed more fully than anyone else in these column.'; 
the inadequacy of the tax on S. A., and the incongruity 
of basing time allowances upon the theorem that speed 
varies as the V L, and calculating them upon the as- 
sumption that the V L = L-l-^s A. 
or some other term manufactured in like manner. But 
he does not see that whenever S. A. has been appro- 
priately taxed in proportion to its effect on speed, any 
other term is not needed in a rating formula. 
He points out that there is nothing to warrant the 
assumption of the N. Y. Rule that speed varies m- 
versely as the ^VD; but he fails to perceive that the 
rule would be improved for measuring purposes by 
leaving out the factor D. 
And he has overlooked the important error of the 
N. Y. Rule, and all other rules of that type; viz., thai 
they undertake to combine in one formula two inde- 
pendent and incompatible functions: the rating of yachts 
for time allowance, and the control of form. The term 
'VD was put into the N. Y. Rule as a divisor, not be 
cause the authors of that rule believed that speed 
varies inversely as the square root of the ^VD; but be- 
cause they knew that this factor would tend to encour- 
age the building of yachts of larger displacement, which 
is desirable, and because they guessed that allowances 
for °VD would be about right to produce the kind of 
underwater body desired. 
It is this futile attempt to kill two birds with one 
stone, though the birds are not in range, which makes 
the current rules illogical absurdities, and failures in 
controlling design within desired limits. The finest 
curio among formulje of this kind is that of the Sea- 
wanhaka Club; viz., RL = L. W. L. + ^ VSA 
-f (B 4- B^) — B" -t- (B" -f Di D2 -f Da) — 3 1-3 
VMS. So far as we are informed, time allowances are 
figured upon the assumption that speed varies as the 
square root of this combination. 
The guarded proposition found in sundry j^acht club 
books that "within economic limits opportunities for 
speed vary in different vessels as the square roots of 
their respective lengths" has been a fruitful source of 
confusion, which its terms do not seem to warrant. 
Mr. Poor takes this to mean that "under normal con- 
ditions" the VL may be taken as a vessel's speed in 
knots, and apparently he thinks this is true without 
reference to the amount of motive power. For later 
he says: "The fact that the larger hull can be driven 
faster by the same power has been demonstrated time 
and again." 
If it has the meaning Mr. Poor gives it, the theorem 
does not accord with facts; and it has long been mis- 
used by all yacht clubs. For example, in 1887, the Sea- 
wanhaka club book, after reciting the theorem, gives 
a table wherein the allowances are only 40 per cent, of 
those which would be required if VL = speed. In 1889 
50 per cent, was given. The Herreshoflf tables, in use 
by the New England Y. R. A. in 1888, gave about 52 
per cent.; and now, according to Mr. Poor, the N. Y. 
Club gives 80 per cent, of the allowances that would 
be due if speed = VL. In a recent elementery text- 
book of naval architecture by E. L. Attwood, the 
author says: "That in full-sized ships driven at a mod- 
erate economical speed" the speed = .5 to 6.5 VL; for 
mail steamers and battleships, .7 to i VL; for cruisers, 
I to 1.3 VL; and for torpedo boats, 1.9 to 2.3 VL. 
Fronde's law provides that, "In comparing similar 
ships or ships with models, the speed must be propor- 
tional to the square root of their linear dimensions." 
That is to say, taking Mr. Poor's example, if a yacht 
36ft. long has a speed of, say 6 knots, the corresponding 
■speed of a similar yacht (having sufficient sail) looft. 
long, would be ^^§- = 1.66 times 6 knots = 10 knots. 
In other words, the rule fixes the ratio of the speeds, 
but does not determine the absolute speed of either 
yacht. This, the writer understands, is the meaning of 
the theorem that is used as a basis for time allowance 
tables. 
Froude's law also provides that the_ resistances of 
two similar vessels at their corresponding speeds will 
be as the cube of their linear ratio: Thus, in the above 
example, the lOoft. yacht at 10 knots would have (2.8)' 
= 21.95 times the resistance of the 36-footer at 6 knots, 
and would need increased sail in the same proportion. 
Mr. Poor maintains that length is a factor in "pro- 
ducing speed," and he. alleges that "the fact that the 
larger hull can be driven faster by the same power has 
been demonstrated time and again." 
This last statement needs considerable qualification. 
It is not true of vessels driven at ordinary speeds, or 
of sailing 5^achts at the speeds which they can attain 
by their own sail. In general, increase of length (mo- 
tive power being constant), decreases speed by increas- 
ing skin friction. The wave-making resistance of long 
vessels at high speeds is less than that of short ones; 
and at certain very high speeds, when the resistance 
from wave-making is considerably larger than the 
skin friction, a Jong vessej might save enough in wave- 
SPIDER. 
Designed and built by the Herreshoff Mfg. Co. Owned by E. M. Stcne. 
Plioto by N. L. Stebbins, Boston. 
making resistance to more than ofl^set her increased 
skin friction over a shorter vessel. In such case her 
total resistance would be less than that of the shorter 
vessel. But these cases are not found in the racing of 
sailing yachts. According to theory, for moderate 
speeds, the resistance varies (i) as the immersed sur- 
face which varies as L", and (2) as the square of the 
speed, which varies as L; so that as noted above, theo- 
retically, the resistance of two similar vessels of dif- 
ferent lengths at different speeds will be proportional 
to the cube of their linear ratios. And Mr. Froude 
found this to be true by experiments. 
The singular results obtained by him at high speeds 
in towing models havmg long parallel middle bodies, 
have no bearing upon the question of rating rules for 
yacht racing. 
That L or D or B cannot "produce" speed must be 
obvious to anyone who will stop a moment for reflec- 
tion. They may all modify speed by modifying resist- 
ance. The only factor which can produce speed mani- 
festly is motive power— sail. When the whole of S.A. 
has been taxed nothing remains for legitimate taxation, 
because nothing else produces speed, or alone measures 
speed. If S. A. were kept constant, all the factors 
which make up resistance would together be a measure 
of speed; and they might be used for that purpose if 
their proportional influence could be ascertained and 
expressed in figures; but it cannot. Nothing is gained 
by attempting to use fractions of more than one meas- 
ure. A yard stick is a complete measure; and using 
parts of two or more, adds nothing to the accuracy of 
a measurement, and is more inconvenient. 
Negative speed factors, like D and B, should not 
be introduced into speed formula by way of rewarding 
hindrance to speed, because a rating rule for racing 
yachts should tend to encourage the development of 
speed, and should be designed only to calculate the 
handicap which a yacht should suffer by reason of hav- 
ing an excess of motive power. In other words, there 
should be no penalty upon the skill of the designer. 
From a racing point of view the best designer is the 
one who can get the most speed with a given motive 
power. 
The fact that it may be necessary or expedient to im- 
pose certain restrictions upon design and construction, 
in order to have safe and desirable racing yachrs. has 
no more to do with the logic of the rules for handicap- 
ping purposes than the fact that it may also be expedi- 
ent to require certain small boats, life buoys and 
anchors to be carried during races. Such matters can 
be attended to without interfering with the rating for- 
mula. 
Notwithstanding the unsoundness of the assumptions 
concerning the relations of the formula factors to 
speed, upon which the current type of rules is based, 
their failure as handicapping rules is not of great 
moment, because, in order to escape the results of these 
defects, yachts are largely built up to the limit of their 
class, so that the allowances are small in amount. The 
abolishing of time allowances would probably be ad- 
vantageous. It is in its function of restricting the 
building of freak yachts, and of encouraging the build- 
ing of good, seaworthy yachts that the rules fail com- 
pletely. And could any other result be rightfully ex- 
pected? Suppose any yachtsman or engineer were 
given a commission to make a regulation to prevent 
the building of light displament yachts without refer- 
ence to any other consideration. Is it conceivable that 
he would look up the regulations governing handicap- 
ping, and try to work them over into a form which 
would also serve the purposes of his problem, and yet 
not injure their efficiency for handicapping? Or would 
he be likely to state in plain terms the minimum dis- 
placement in proportion to length, permissible for any 
yacht, with suitable restrictions as to its distribution in 
respect to height and width? 
There is no good reason why the two matters of 
measurement for time allowance and restrictions on de- 
sign cannot be treated separately, and the advantages 
of considering each by itself are evident. 
What will be the result of attempting to regulate the 
matter of displacement by putting the ^VD into the 
measurement formula as a divisor? First, it will injure 
the rule as a measuring device. Second, it will necessi- 
tate years of experimental designing, building and rac- 
ing of yachts at large expense to discover what amount 
and arrangement of displacement will give a yacht the 
best combination of speed and time allowance under 
this formula. And the chances are a thousand to one 
that the successful form will be found to have either 
more or less displacement than is desirable, or will 
have it distributed in an awkward form of hull. Worst 
of all, no advance will have been made in the matter 
of measurement, and no commensurate improvement in 
designing. 
The genius and skiU of yacht architects should be 
devoted to the discovery of forms of least resistance 
instead of to the engineering problem of carrying^ the 
largest sail on the frailest hull with the smallest and 
lightest spars and rigging; or to the problem of devis- 
ing the best means to "beat the rule." 
Sextant. 
YACHTING NEWS NOTES. 
For advertising relating to this department see pages ii and iii. 
There was a report current last week to the effect 
that the gasolene yacht Roamer, owned by Mr. H. C. 
Roome, had been lost on Rum Bay in the Bahamas.- 
W^hen an attempt was made to verify the report, it 
was found that the yacht that was wrecked was not 
Mr. Roome's Roamer, but a schooner of the same 
name owned by a Colonel Campbell, which boat sailed 
from Jacksonville over two weeks ago. She was built 
in Beaufort, N. C, in 1899, and was 77ft. over all, 
66ft. on the waterline, 26ft. beam, 4ft. deep and 5ft. 
draft. She was 55 tons, and vvas formerly owned by 
Mr. C. E. Whitehurst, of Baltimore, 
H 
There are building at Mr. Willard F. Dov^ms' yard 
at Bayshore, L. I., three one-design boats from de- 
signs made by Mr, Henry J. Gielow. The boats are 
26ft. Sin. over all, 17ft. waterline, 7ft. 6in. breadth and 
2ft. draft. There are 1,000 pounds of outside ballast on 
their keels, and the boats will carry 424 sq. ft. of sail 
in their mainsails and jibs. The boats are to be deliv- 
ered complete to their owners on May 15, 1904. It is 
very likely that several more boats will be built from 
the same design. 
K K K 
The South Coast Y. C. will soon have a $15,000 club 
house built at San Pedro, Cal. 
H K It 
Mr. Edson B. Schock has opened a brokerage de- 
partment in connection with his regular business as 
naval architect. Mr. Schock was formerly with Mr, 
A. Cary Smith, and also had charge of the construction 
of the Holland torpedo boats and the U, S. cruiser 
