Boating and Sailing.pdf - Moja ladja

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Part 1: Getting Started in Boating
The power in a powerboat comes from many sources. In this chapter, I’ll tell you about
the types of motors used in boats and discuss the costs both for their purchase and operation.
Portable Power—Outboard Motors
The first engines most boaters use are outboard motors, so let’s look at those first.
Outboards are engines featuring an integral drive system including a drive shaft and propeller,
all in a single unit that can be moved from boat to boat. All of them still look more
or less like the motor designed by Wisconsin inventor Ole Evinrude and patented in the
United States on September 16, 1910. Evinrude went on to found Outboard Marine
Corporation (OMC), one of the world’s largest manufacturers of outboards.
Boater-ese
The propeller on a boat
is commonly referred to as the
prop. The shaft that connects it to
the drive shaft from the powerhead
is called the prop shaft.
Boater-ese
In nautical parlance, an
engine is the power unit itself
without the drive train and propeller.
A motor is a complete
power unit including a drive shaft
and prop. Thus, inboard and
stern-drive power plants are usually
referred to as engines, while
outboard power plants are usually
called motors. (And just to
make things more confusing,
a motor is also an energyconversion
device such as an
electric or hydraulic motor that
draws power from an engine
located elsewhere on the boat.)
An outboard motor includes a gasoline engine mounted
at the top of a long shaft and a prop mounted at the bottom.
The motor clamps on the stern of a boat, and the
whole thing—motor, shaft, and prop—pivots to steer
the boat. If the boat already has a steering mechanism
in place, such as a tiller and rudder, the motor stays stationary
and the boat steers like normal.
The outboard concept was particularly useful in the
early years when mostly smaller boats were used for
recreational boating, and a single motor could easily be
moved from one boat to another. Individuals who
owned these light, portable motors could carry it in the
trunk of their cars to boat rental operations anywhere,
and in the booming economy before 1929, lots of folks
had spare cash to spend. Thus they made Ole Evinrude
and his offspring quite wealthy.
Outboards today offer the advantages of high performance,
low weight, and push-button trim and tilt of the
lower unit, which makes it easier to control the running
attitude of a boat—the angle of the boat bottom to the
surface of the water—and makes it easier to operate in
shallow water. Outboards are also easy to steer due to
the “vectorable” thrust—that is, the propeller itself can
be angled to push the stern to one side or the other.
The following figure shows the lower unit of an outboard.