| Bow: the boat's
forward tip or nose.
Bulkhead: a
vertical internal member that supports the hull.
Chine: the
seam where the bottom of the hull meets the sides, forming the lower edge
of the Freeboard (see below). This line is usually visible from just above
the water line down.
Coupler: a
device that connects the drive shaft to the engine or motor.
Drive dog:
this attaches the propeller to the prop shaft.
Flex-cable drive: a
cable that serves as the drive shaft and transfers power from the powerplant
(in the center of the boat) to the prop (at the rear); it's held in place
by a drive-shaft tube. This allows the powerplant and prop to be mounted
at different angles so installation is easier.
Freeboard:
the boat's flat side panel. The upper edge is the sheer, and the lower
edge is the chine.
Keel: a monohull's
bottom centerline, where it comes to a point. It's a mono's backbone.
Prop: this
produces thrust by spinning and pushing against the water. It can be made
of plastic, aluminum, or brass.
Rudder: a flat
piece of aluminum, brass, or plastic, that steers the boat by deflecting
water to one side or the other. It is linked to a servo by a tiller arm.
Shaft drive: a
rigid tube or shaft that transfers power to the prop. This system is more
efficient than a flex-cable, but it requires that the engine and prop be
mounted at the same angle, or that a U-joint be used.
Sheer: the
seam where the side of the boat meets the deck to form the upper edge of
the freeboard. The sheer is roughly parallel to the water line above the
chine. |
..... |
Skeg:
a straight, blade-shaped fitting usually attached to the keel or the strut
to help turn the boat.
Strakes: ridges
molded into the hull and running parallel between the keel and the chine.
They prevent water from climbing up the side of the hull, so they reduce
drag. In high-speed corners, strakes prevent a boat from sliding sideways.
Stringers:
support strips running forward and aft that support the hull and deck.
Strut and strut bracket:
a device that's usually attached to the transom and holds the prop and
prop shaft at a precise angle.
Stub shaft:
a short, solid shaft supported by a strut on which the prop is mounted.
The stub shaft is attached to the drive cable or the drive shaft with a
universal joint.
Stuffing box or tube:
a metal tube inserted through the hull that allows the drive shaft or drive
tube to pass through the hull and on to the prop without letting water
in.
Transom: the
vertical panel that forms the boat's rear. This is usually the surface
to which the rudder- and prop-mounting brackets are attached.
Trim tabs:
also called ride plates, these flat tabs are attached to the transom's
bottom edge to adjust the boat's ride angle (nose up or down), or to correct
torque-induced hull roll.
Turn fin: a
vertical blade attached to the back of a hydro's sponson or to the corner
of a mono's transom; it improves cornering performance.
Universal joint: also
called a U-joint, this connects the drive shaft to the prop-mounting assembly
or stub shaft. It bends through a full 360-degree rotation thus allowing
the prop assembly to be set at the optimum angle without affecting the
drive-shaft angle. It is also used with articulated steering drives in
which the rudder and the prop move as a single unit. |
