92 COMPARATIVE TESTS OF BILGE KEELS AND A GYRO-STABILIZER 
I remember Admiral Taylor telling me years ago what an astonishingly small helm 
angle impeded a ship; a large retardation comes about through even a small helm 
angle. When you calculate it, you find it is about 17 pounds per square foot retardation, 
with a helm only three degrees over. When the ship is rolling heavily, the busiest 
man on the ship is the helmsman. The ship is trying to make a sinuous course, yawing 
continually, and the helmsman does everything he can to try to correct it, his helm being 
nearly hard over much of the time. When we consider the further loss due to bad angle 
of attack, owing to yawing, and losses due to increased pitch due to roll, which we are 
learning so much about now that we can suppress it entirely, we find there are three 
distinct and important sources of power loss that were not included in these tests, together 
with a fourth one remarked by Commander McEntee regarding the lifting of the pro- 
pellers alternately as the ship rolls. This loss is less in still water, but there are at least 
three losses of efficiency in the way I have outlived. 
The curves shown by Commander McEntee are exceedingly interesting. 
When we put the first stabilizer on the Worden about ten years ago, we found 
that the stabilizer actually would bring the vessel with the masts up very promptly 
when the wave increments were estimated to be considerably beyond the theoretical 
stabilizing capacity of the installation. You must not think that there are any ghosts 
in the gyroscope, because there are not. When we calculate what the stabilizing and 
wave-quenching ability is, we find it always right there, because when we turn on the 
precession in the acceptance test of rolling the ship she will periodically start out and 
then gradually slow down, go lazily along, and one becomes convinced that it will not 
reach the point that theory says it should reach on any kind of indicator, but she finally 
and inevitably gets there. There seems absolutely no difference between the theory 
and practice in gyroscope moments. 
The reason is apparent when it is considered that the gyroscope deals in stresses 
only and does not deal in power nor anything where you have to subtract or add for 
unknown quantities or find any factor such as resistance—these are taken care of in 
getting the wheel up to its spinning speed. Nowif the wheel is spinning at any given 
speed and we precess at some known angular velocity, the stabilizing moments imparted 
to the ship are those calculated, absolutely to the 100 per cent mark, and we do not have 
to use any factors or make any deductions. 
There is another point in connection with the moving pictures. I wonder if you 
noticed once or twice that the model shipped seas—you would notice that a splash would 
come over her side now and then, but only when she was rolling heavily or dipping over 
towards the direction of the wave-maker. That is the very thing which Sir William 
White, when over here in consultation on the practical working of the gyroscopic stabil- 
izer, predicted. He said: ‘‘If you succeed in stabilizing a ship, that ship will stop 
shipping seas.’’ We all felt somewhat doubtful about it, but you noticed, as soon as the 
stabilizer was thrown on and the deck became level with the full sea running, no splash 
ever came aboard. We found that with the Worden the decks were dry when she was 
stabilized, but when she was not stabilized, sometimes on the lee side of the ship, there 
being no necessary connection between the period of the ship and the period of the sea, 
the waves would come aboard quite frequently. I would like to have the slides now. 
One of them has to do with Commander McEntee’s curves. 
Plate 32 looks as though it were a very substantial argument for the use of bilge keels, 
where we find that these keels brought the model down to one degree total roll in forty 
