ON A MODEL OF THE U. S. AIRCRAFT CARRIER LANGLEY. 95 
power in a seaway, I think something may be done along that line in the model basin, 
but we shall not get the real answer until we try a real ship. The Navy Department 
is arranging to conduct tests of the Henderson, and I hope, if we get the results I look 
for, to have a paper next year which will show the actual power and speed changes 
between a ship which is stabilized and a ship which is unstabilized at sea. This, after 
all, will be the real answer to the problem. 
Mr. SmitH:—The model-basin power, and the power that you obtain during a 
trial trip, under ideal conditions, is what you might term the ideal horse-power of the 
ship. The service horse-power under average conditions is another thing. What I 
am trying to get at is the ratio between the ideal horse-power and the service horse- 
power. 
Tue CHAIRMAN :—We are indebted to Commander McEntee for his excellent paper, 
and while not desiring to indulge in a discussion of it, I will say that the ordinary and 
unscientific method of obtaining sea speed of the ordinary vessel is to give it enough 
power to make about a knot more than the contract requirements call for as regards the 
speed. The owner usually insists on an excess of power, because his ships are built to 
operate on schedule; and the model conditions and the trial conditions are the best 
conditions, and not the conditions which the ships meet with in actual service, so that 
we show an excess of power to give the extra speed in unfavorable conditions, the speed 
being especially necessary to the owner under those circumstances. Many ships have 
had the reputation of making speeds at sea that have been very materially aided by the 
Gulf Stream and other natural causes. 
The next paper, gentlemen, is No. 7, entitled ‘‘Surface Condensers,’’ by Mr. Luther 
D. Lovekin, Member. 
Mr. LoveKkin:—What led me towards making this special form of condenser 
was the number of experiments which I had been conducting on heat transmission. 
As mentioned in the paper, I made a number of tests with five-eighths-inch tubes, 
having tubes of different diameters surrounding the said five-eighths-inch tubes, and 
much to my surprise I found that, as far as I went, the larger the tube surrounding the 
five-eighths-inch tubes the better results I obtained. I did not care to experiment with 
any larger tube than the two-inch tube surrounding the five-eighths-inch tube, as I 
knew the results would be impracticable, and so in making the tests I confined myself 
to two sizes of tubes, the lower limit at one and one-half and the higher limit at two inches. 
I found, by testing a tube four feet long, with all conditions the same, one with the 
14-inch inside diameter and the other with a 2-inch inside diameter surrounding said 
54-inch tube, that I obtained a temperature rise of 60° and 100° respectively. 
This clearly proved to me that there was something in the proper spacing of the 
tubes in a condenser; in other words, I think we have all been inclined to space tubes 
too closely. I then designed an apparatus with the regular spacing, with about 100 
tubes, made several tests, and finally sent it to Annapolis. JI found the difference 
between tubes en masse and a single tube was considerable. I then designed the con- 
denser for the battleship Tennessee, and I had expected to have the results of the trial 
of the Tennessee for this meeting, but, unfortunately, she met with an accident and 
has not completed her trials. 
