Prop Guard® is
made to surround the propeller like a nozzle. This designed
nozzle action moves water with a controlled directional
force which gives the boat improved handling and more
power. This nozzle action is accomplished with no moving
parts to adjust or replace. Whether you have an outboard or
stern drive, Prop Guard® will increase propeller
efficiency, decrease fuel consumption and improve boat
handling while reducing hull and engine stress. Technical
testing of the Prop Guard® has proven that the
performance of pleasure crafts are actually enhanced by the
installation of the Prop Guard®.
the Prop Guard® increase propeller
Optimum performance of
any vessel is dependent upon the design match between the
type of engine, its propulsion system and the type of hull.
The delicate balance can easily be upset with an under
powered or over powered engine. Even a perfectly well
designed propeller may perform miserably if that propeller
is placed behind an oversized or overloaded hull. Any
problem with these elements can result in poor performance
and handling for a vessel.
Guard® , even with a technically unbalanced craft can
increase the thrust of the propeller. The loss of kinetic
energy due to rotational flow in the water downstream of
the propeller can be partially recovered by the guide vanes
of the Prop Guard® as it creates a counter rotation
vortex, reducing the torque effect of the rotating
propeller. The hydrofoil nozzle configuration of the Prop
Guard® creates forward thrust, which overcomes its own
drag and also provides an effective trim without drag.
Nozzle propellers produce more thrust than open propellers
as the nozzle produces greater dynamic lift for the boat
and permits it to achieve faster acceleration and
eliminates the need for existing or additional drag
producing trim devices. In a steep turn, boats tend to turn
on their center of gravity and the propeller loses its bite
in the water creating uncontrolled rev-ups, as the stern of
a boat and the prop moves tangential to the center of
gravity of the boat. This is eliminated as the greater
lateral area of the nozzle produces a larger effective
rudder area. Prop Guard® increases the thrust
significantly to overcome handling problems.
How does the Prop
Guard® increase boat handling?
In tests, vessels with
Prop Guard® installed were put through tight figure 8
turns. The handling characteristics were greatly improved,
as greater lateral area of the nozzle produces a larger
effective rudder area. There is significantly greater
steering control at high speeds, when the vessel made 360
degree turns in 30 to 40 feet compared to 60 to 80 feet
with an unguarded propeller. The stopping ability of the
boat is also dramatically increased as the nozzle presents
a greater blockage area.
the Prop Guard® reduce hull and engine
allows a vessel with a planing or displacement hull to be
trimmed so efficiently that porpoising or pounding of the
hull can be greatly reduced. The fact of less pounding on
the hull should reduce hull stress. When a boat is
porpoising, sometimes the upper portion of the propeller
will be in and out of the water allowing the engine to rev
and release. The improved handling can also help reduce
this type of engine stress.
the Prop Guard® make a vessel safer?
There are no
“minor” propeller accidents. Installation of
the Prop Guard® on all propellers would greatly reduce
prop blade injuries to humans and marine life. The added
thrust also allows for better handling control of the
vessel. The Coast Guard, life guards and military vessels
are preparing to order Prop Guards® because of the
greater propeller safety factor and increased vessel
control that they can achieve.
In a statement from
the celebrated Philadelphia court case of Fitzpatrick vs.
Madonna & Outboard Marine corporation, Dr. Robert
Taggart states that, “the Schultz nozzle is a basis
of a near optimum additional device to provide protection
from outboard motor propellers.” Prop Guard®
combines the majority of the recommended features into a
structurally and hydrodynamically sound design.
Current Federal and
State lobbying groups predict a mandatory propeller guard
law to be mandated in the very near future. Florida
predicts the prop protection law could be passed in the
near future to protect the manatees and humans. Marine
insurers are offering premium reductions for policy holders
who install safety devices on their vessels now, with
further incentives for propeller guards coming.
What is a Prop
Prop Guard® is
the next patent generation of propeller protection from the
noted engineer and inventor Wilderich Schultz. Mr. Schultz
has spent his life creating products that improved safety
and performance for many aircraft and marine products. Mr.
Schultz’s father invented the first propeller nozzle
guard, the “Kort Nozzle” for canal and river
boats in the early 1930’s. Mr. Schultz took this well
proven product and used present technology and hydrodynamic
principals to adapt it to the needs of today’s
boating industry. Now with the joint engineering and design
modifications between Mr. Schultz and Mr. Morrell, the new
Prop Guard® is a
two piece plastic injection molded cage that will
completely cover the propeller. The Prop Guard® is
attached by a specially designed clamp system and bolts.
The Prop Guard’s® two halves are attached like a
clam shell to the cavitation plate and the skeg of any
outboard or stern drive motor. The easy installation can be
accomplished by anyone with simple tools in about 20
minutes.How is the
Prop Guard® different from other propeller
The differences of the
Prop Guard® over the current market propeller
protectors are many. First, the Prop Guard® is made
out of a light weight but strong, high impact, flexible
injection molded plastic. This allows the guard to work
without having the heavy weight and danger of the metal
guards that are on the market today. Metal guards can
corrode, and with a hard hit, the metal guard can be pushed
into the propeller causing possible propeller damage.
Besides propeller damage, the metal cage can break into
metal fragments that could cause personal injuries and gear
The one major
difference that the Prop Guard® has over any other
guard is the Prop Guard® will improve the performance
of the propeller. What this means is that if you can
improve the efficiency of the propeller, you will improve
the performance of the boat. The Prop Guard® is the
only product not only designed to protect, but to improve
the handling of a boat.
The purpose for the
Prop Guard® is to provide a product that will protect
a family from deadly propeller accidents and give the boat
owner the excitement and enjoyment of improved performance.
The Prop Guard® provides important benefits for the
boat owners throughout the world. Boat safety and
performance is a world wide need, not just an American
issue. Boating accidents happen worldwide, therefore, the
Prop Guard® is a truly global product.
As you can see, the
Prop Guard® is a well designed product which offers
many benefits to the boating industry.