THE ‘‘ HD—-4’’—NUTTING. 209 
ing left behind. The wind on your face is like the pressure of a 
giant hand and an occasional dash of fine spray stings like birdshot. 
Baddeck, a mile away, comes at you with the speed of a railway 
train and you brace yourself for the turn as Baldwin drives her 
through the narrow passage inside the island. You feel that she is 
going to skid as he starts to make the turn at full speed, but she 
does not. Just as the struts of the rudder set are sufficient to steer her, 
so are those of the main planes sufficient to keep her from side slip- 
ping. Even more startling is the fact that she doesn’t seem to heel a 
degree as she makes the turn. It is unbelievable—it defies the laws of 
physics, but it is true. 
Then you notice that you are traveling over waves a foot and a 
half in height—waves that would take the bottom out of an ordinary 
hydroplane traveling at such a speed. There is no pounding or 
jolting of the kind with which everyone who has ridden in a racing 
hydroplane is familiar. A slight undulation like that you feel in a 
Pullman car is the only sensation. 
Another noticeable thing is that when hitting a wave there is no 
retarding of the machine as would be the case with a surface plane, 
and in this connection it might be interesting to note the effect on the 
hydrofoil supports at top speed. It will be seen from plate 7, figure 
1, that the forward hydrofoil sets are hung from a steel tube 
which passes through the body of the machine and that the axis of 
the struts is several inches forward of the center of this pipe. This 
seemingly insignificant length of lever arm through which the “ lift ” 
is applied is sufficient to neutralize the “ drift” on the hydrofoils 
3 feet or so below the point of support. At full speed, instead of a 
tremendous backward pull on these struts as would be expected, the 
tendency is actually forward, and the supporting member running 
from the strut to the under side of the deck, instead of being in 
tension as would be expected, is actually in compression. 
Then Baldwin gives you the wheel and timidly you start to try 
it out. You feel that something must surely let go if you give her 
any helm. But nothing does and you find that she steers with the 
ease of an automobile. 
As you get accustomed to the speed your confidence grows and soon 
you find yourself out of the cockpit lying over the edge of the deck 
on your stomach to see for yourself what is going on below. The 
“ preventer ” at the bow is entirely clear of the water except for the 
tip of an occasional wave and all of the main sets are out except for 
the two lower ones on either side. Each square foot of submerged 
steel is carrying over 2,000 pounds. 
Baldwin designed the HD-4 to demonstrate the possibilities of the 
type for carrying loads at extreme speed, efficiently, and with com- 
