The sun. [volume] (New York [N.Y.]) 1833-1916, 1899-09-27
MAY POLISH THE TOPSIDES.
PAINT WILL BE REMOVED FROM CO.
LUMBIA'S HULL, IT IS SAID.

If. after what Prof. Thurston has said about
the difference in resistance between smooth
metal and painted surface. the Columbia ap-
pears with painted topsides to battle with the
Shamrock. yachtsmen and yacht designers will
be much surprised. The subject 10 still n We
hicle for lively discussion among those who
know anything about boat and not few per-
sons are so convinced by Prof. Thurston's de-
monstration that they believe unless the cup
defenders sides are polished she will lose the
race.
1t was learned that the matter was talked
ever by Mr. Iselin and Capt Barr on board the
Columbi yesterday. or course. neither OF
these men would say that the subject came up
in rather an extended conference held during
the morning, but from another source the in
formation was obtained that Prof Thurston's
report had made considerable impression on
both Mr.. Iselin and Capt Barr, and the same
authority says that when the Columbia Is
placed in the dry dock at the Brooklyn Navy
Yard tomorrow. tho white paint on her
topside will be scraped Off and her metal
sides polished This statement would in
dictate that Mr.. Iselin and his associ-
ates hao decided in favor OF the proposition
advanced by Prof. Thurston. 1t may have
been intended to polish her topsides from tho
start. but II so Prof. Thurston's statement can
only have strengthened Mr.. Iselin's belief that
ho was Tisnt' II, IOWeNtT, LILO ulTtVlOTS VI tue
CUP defender had been keeping their plan u
secret with view OF administering q solar
plexus blow to the challenging yacht. Prof.
Thurston's published views have rendered the
secret useless.
1t is evident that Designer Fife has been
reading the newspapers, for as soon as tho
Shamrock reached the Erie Basin yesterday
the crew were set to work scraping the green
paint Off the top sides 1t will be removed as far
tha ,nl,t tho, ill
be FURNISHED and made az smooth as glass No
one identified with the challenger would say
why this was being done. but it was doubtless
due in no small measure to Prof Thurston's
report
John Hysop. tho official measurer OF the
New York Yacht Club. who has had plenty OF
experience with yachts of all sorts. said yester-
polished bronze, that he supposed Prof. Thurs
Ten had figured carefully, on the question.
whether paint would retard yachts speed h Q
could not tell, but he said
II have experimeptei with paint and pot
smoother surfaces than potlead. The lat ter
when first put on Is very smooth and makes q
RENE Der some Years ago potieadine va chit
and then putting her in race. After the boat
hand over the side ADoe the waes the boat
was beautifully smooth. but underneath it was
Spd G p1n9 is firm oe
success. with this way of preparing the under
body OF yacht, but my eS perience has bee n
much softer than the metal with which these
racing Yachts are now constructed that it
ferng more resistance to the water. This how
ever. is subject that needs very careful OK
animation before decided opinion should be
The difference in resistance between paint
accurately determined by exhaustive expert |
m Irs made In both this country and ENGLAND;
Robert Em"nd froude. V Who is a At I the head OF
the Admiralty Experiment Esta blishment The
data wheh he has s%thered is doubtless in the
in figuring that in thirty m lie race the painted
top sides OF the Columbia would retard her
subject OF resistance like all scientific matters
T. ilsult one for the ordinary mind to grasp
ture. which is a treatise on laws to govern
the resistance OF bodies moving in water. Chap |
Until within the last forty years it was gem
orally supposed that vessel on being impeed |
head resistance. the measure OF which was the |
area o. the greatest transverse section and the
OF ma ns by snI
recently those made by Mr., Froude show that |
no such direct head resistance can exist,-that
Is. no resistance analogous to that n board |
WG9n m1 Ss r wh on oeE movsd
sipal sourses o. resistance to be dealt with
skin friction or SIX in reslstance,' and the
waves. Another resistance due to tbs making Of |
eddes lie of minor Importance. BY surface frlc- |
ton is meant the adhesion of the water to the |
surface OF the vessel and it exists at all speeds:
Its qua ty il dependent upon the smoothness |
limitations the fraction gradually decreasine
az the after end OF the vessel is approached) to |
the length OF the surface acted upon.
referring to the fact that fractional resist |
and is sTeatest at the ,sntronee. MI. Fr %ids
the part which goes first must give motion TO |
the water in the direction in which itself is |
face viii succeeds the first will be rubbing |
not against stationary water but against water
therefore cannot experience SO much resist
anGe from It However. with bodies OF tlftyfeet |
eaua ale We f the 'ne
lace and this is commonly done for all over |
:Upon a BODY fifty feet in length. moved at a
velocity , OF six knot an hour Mr. Froude found
q Wetted surface for bIack ead eaus snrfase
ton, .25o FOR length over ity feet the " mean
ceeding hf,y feet, the value given can be taken
power Of the speed: but in the case Of very
rough surfaces. such as bottom fouled bv
power OF the speed. and may even reach the
cube OF the speed in the case Of vessels which |
have become overgrown with large barnaces
This may not be very Ineligible to the lay
mind. bnt that part relating to the compare;
tive resistance OF clean copper sheathing and
smooth Vanished surface can be readily un-
derstood. William Gardner Of the firm OF
Gardner & Cox. naval architects. used it as a
basis for talk with reporter of THE Sun
yesterday. He said:
Prof, Thurston is right. Tho difference in
the resistance of white paint aud polished |
bronze might easily win or lose a race for the
Cup. l think the directors of the Column hia
viii surely scrape OF the paint on her tor sides
and polish the metal underneath it, Take the
comparison made by Mr. Fraude between the
resistance of clean copper sheathinR and nlack
lead. which 10 in figures as 2i6 is to 24S per
square foot o. wetted surface, and suppose two
boats sail 24S minutes, or about four hours.
everything else being exactly equal. the boat
with the polished copper body would Leaf the
black loaded boat by two minutes. That is the
Theoretical difference but actually the differ
ence Ia about one minute and half. Prof
Thurston has evidently prepared his figures
carefully and | think they are to he relied
upon. | have data which would prove tho
same thing, but unfortunately they are not at
hand.
In reaching or in windward work either
yachts port or starboard top sails are CON
stanty under water and this topBdeS surface
may be recorded in some cases to be as much