PART ONE:DRIVETRAIN INSTALLATIONS
Figure 2-5. Metal hull strut construction: struts to girders
Figure 2-6. Metal hull strut construction: struts to floor or frame
Water Inflow to the Prop
A common cost-cutting measure on off-the-
shelf struts is to make the strut legs square
in section. In fact, square-section strut legs
create only slightly more drag than the flat
oval section shown in Figure 2-3, and this
leads many to believe that they compromise
very little. The problem with square-section
strut legs isn’t their drag, however, but their
effect on the propeller; these squared-off cor-
ners can create turbulence ahead of the prop.
Theoretically, true airfoil-section strut legs
interfere the least with water flow to the
prop. In practice, the symmetrical flat-oval
section shown in Figure 2-3 is nearly as good
and is simpler to build. Boats operating under
20 knots can get by with flat and square strut
legs that are slightly rounded at the leading
and trailing edges, but these still won’t be as
quiet as the shaped strut section shown in
Figure 2-3.V-Strut Leg Angles
Since V-struts have two legs to impede water
flow, you want to make sure that two legs
can’t line up with the blades at the same time.