ONR Hydrofoil Boat XCH-6 211 
contour, a sharp leading edge, and a blunt trailing edge. The strut cross section employs a 
parabolic forebody and a tapered afterbody; the two regions of this section are separated by 
a step. 
The tail hydrofoil (Fig. 5) employs zero dihedral and is supported on the forward half 
of the propeller pod; the pod is supported by a single strut. Figure 6 illustrates the strut 
and foil cross sections. The tail hydrofoil section is of symmetrical, subcavitating design 
and incorporates a low thickness ratio. A parabolic cross section with a blunt base is used 
on the tail strut. Propeller pod fineness ratio is approximately 8.5. 
Fig. 5. The tail strut, propeller, and hydrofoil 
The forward, cruise foil elements and lower struts are fabricated from solid stainless 
steel. Upper regions of the forward and tail struts are fabricated from heavy-gage aluminum 
plate. Diagonal foils, tail foil, lower tail strut, and propeller pod are machined from solid 
aluminum. 
Each forward, cruise foil element is attached to its supporting strut by flush-head 
bolts which are inserted from the bottom side of each foil element and which extend into 
tapped holes of the struts. Diagonal to cruise element attachment is similar, with bolt 
