What propeller will get the best performance for hole
shot, midrange and top end?
There is no perfect propeller. Correct propping for a Stingray Boat is going to involve
a compromise between hole shot, midrange and top end performance. Depending on the specific
boat/engine combination, some propellers will perform better than others at attaining all
three objectives. The best hole shot is generally achieved with a propeller that allows an
engine to gain rpm as rapidly as possible without detrimental ventilation or slippage.
BLACK MAX, ALPHA and HIGH FIVE are excellent propeller families that
would fit this application. Most engines develop maximum horsepower within the recommended
wide open throttle range. Within the range, however, horsepower is usually increased with
rpm. The propeller uses power to transfer a higher propeller pitch (inches traveled per
revolution), and more rake(bow lift) into more speed with a result of lowering engine rpm
at wide-open throttle operation. Mercury offers many excellent performance propellers
including LAZER II, MIRAGE PLUS, and the BRAVO ONE Performance Series.
Mid-range performance is a compromise of the above two applications. Choose the propeller
with the larger diameter that allows the engine to operate in the upper rpm range.
What propellers are recommended for my
Stingray?
BLACK MAX
A great value and a real performer, this three-blade, black, high gloss premium aluminum
propeller is designed for your Alpha Drive or one of similar power. The Black Max is equipped
with the patented Flo-Torq II Drive Hub System for improved durability. Exclusively blended
aluminum also makes the prop easy to repair.
ALPHA FOUR-BLADE
The Alpha is designed to enhance the all-around performance of Alpha Sterndrive-power boats.
These four-blade, high-gloss, black aluminum propellers practically grab the water
compared to three-blade props. The results are noticeably improved acceleration, smoother
running quality and a higher level of reverse thrust and docking characteristics. The
patented Flo-Torq II Drive Hub System protects the drive train and improves durability. For
the power hungry, Alpha One four-blade Performance Series props are quicker to plane with
water skiers and heavier loads. The four-blade ALPHA is the nearest competitor to Mercury's
SS High Five propeller in low-end performance. Top speed will likely be reduced by 2 to 3
miles per hour.
MIRAGE SS
These three-blade stainless high-performance cup props are excellent when it comes to all
around performance and the Duratec finish helps resist metal fatigue and corrosion. Improved
acceleration, better holding and a closer match of speed on dual engine boats are achieved
through redesigned cupping. For up to 415 h.p. Bravo I MerCruiser Sterndrive boats; the Mirage
Plus Flo-Torq II propeller offers robust top-end performance, and the patented Flo-Torq II
Drive Hub System. Extensive testing by Stingray has shown running Mirage propellers on Alpha
drives usually results in a overall loss of performance (especially low and midrange).
BRAVO III SS
Double the propellers, double the fun. No matter how you use your Bravo III drive, these
counter-rotating twin stainless steel props provide exceptional boat handling at various speeds.
Improved operating efficiencies and high-thrust production make these props perfect for any
Bravo III application, from heavy pleasure and light commercial to the high performance
speedsters.
LASER II SS
For those light, easy to lift hulls with plenty of power aft, try a stainless steel
Laser II. This performance-oriented, surface-piercing, high-gloss propeller line features the
exclusive Flo-Torq II Drive Hub System to protect the drive train and improve durability.
Designed to deliver the best top speed your engine and boat package will produce, LASER II is
available in a full compliment of pitches for Alpha Sterndrives. Laser II has thinner blades
to minimize drag and deliver exceptional acceleration. A small hub version is available so that
inline outboard owners won't miss out on any of the action.
HIGH FIVE SS
If you're footing or boarding, the HIGH FIVE series is an excellent blade for towing. The
smoothest running prop available for Alpha Sterndrives, with outstanding acceleration to get
the boat on plane and the skier out of the water. Five stainless steel blades are the prop of
choice for those who depend on performance including nationally ranked tournament anglers, pro
water skiers and flats guides. The large hub version is perfect for bigger V-6s and Alpha drives.
The patented Flo-Torq II Drive Hub System improves durability and protects the drive train, no
matter what brand is mounted on your transom. The HIGH FIVE SS is the best accelerating low and
midrange propeller Stingray has ever tested.
What is propeller diameter?
Diameter is the distance across the circle made by the blade tips as the propeller rotates.
What is propeller pitch?
Pitch is the distance that a propeller would move in one revolution if it were moving through
a soft solid, like a screw in wood. When a propeller is identified as 13 3/4 x 21, it has a
13 3/4" (35 cm) diameter with 21" (53 cm) of pitch. Theoretically, this propeller would move
forward 21" in one revolution.
What is propeller cupping?
When the trailing edge of the blade is formed or cast with an edge curl it is said to have a
cup. Cupped props will usually allow a faster top speed and more midrange efficiency by allowing
more positive trim with less prop slip. Cupping benefits are so desirable that nearly all modern
recreational, high-performance or racing propellers contain some degree of cup. Cupping will
usually reduce full-throttle engine speed about 100 to 200 RPM below the same pitch propeller
with no cup. A propeller repair shop can increase or decrease cup to alter engine rpm to meet
specific operating requirements on most propellers.
What is propeller ventilation?
Ventilation occurs when air from the water's surface or exhaust gases from the exhaust outlet
are drawn into the propeller blades. The normal water load is reduced and the propeller
over-revs, losing much of its thrust. This action most often occurs in turns, particularly when
trying to plane in a sharp turn or with an excessively trimmed-out engine or drive unit.
Ventilation can also be caused by aerated water from step bottom hulls.
Stingray Boats' patented z-plane hull's bottom
allows for less propeller ventilation than boats with conventional hulls.
What is "blowout?"
Many high-performance boaters are aware of a phenomenon that limits their top speed below what
would otherwise be possible with the available horsepower. This phenomenon is commonly called
"gearcase blowout," "propeller blowout," or just "blowout." The current gearcases used by
Stingray Boats will not "blowout" under normal conditions with maximum available horsepower.
What is propeller cavitation?
As a shape passes through water at an increasing speed, the pressure that holds the water to the
sides and back of the shape is lowered. Depending upon the water temperature, when the pressure
reaches a sufficiently low level, boiling (i.e., the formation of water vapor) will begin. The
collapsing action, or implosion, of the bubbles releases energy that chips away at the blades,
causing a "cavitation burn" or erosion of the metal.
The initial cause of the low pressure may be nicks in the leading edge, too much cup, sharp
leading edge corners, improper polishing, or, sometimes, poor blade design. Massive cavitation
by itself is rare, and it usually is caused by a propeller that is severely bent or has had its
blade tips broken off resulting in a propeller that is far too small in diameter for the engine.
(See Ventilation for another common cause.)
Will a stainless steel propeller make my
boat faster?
Generally, yes, a steel propeller will be faster. If the designs are the same, the steel
propeller can be made with thinner blades that run faster and with greater strength. Also, most
stainless steel propellers take advantage of performance enhancing designs to gain even more
advantages over aluminum.
How do I select the right
propeller?
Best all-around performance is achieved when wide-open-throttle (WOT)engine operation occurs
near the top of the wide-open-throttle rpm operating range designated by the manufacturer for
that specific engine (See Stingray Powerboats power options). Improperly propping an engine can
not only reduce performance, but also, in fact, damage the engine.
An engine that does not reach the rated rpm at wide-open-throttle is in an "over-propped"
condition, resulting in "lugging." This severe strain can lead to detonation, piston seizure,
and engine damage. On the other hand, an engine that revs past the recommended rpm will have
higher than normal wear and can also be damaged by fatigued parts breaking and passing through
the engine. This is why it is so critical to be sure your engine is propped correctly
for your boat/engine combination and the type of boating you want to do.
To make this selection, propeller charts are published as guidelines for general applications
of Quicksilver propellers. They are not intended, however, to be an absolute
recommendation, as boats and operating conditions vary. Use the guidelines suggested here, but
remember, the best propeller for your boating needs, can be determined only by experimentation.
You really should have more than one propeller if you use your boat for more than one type of
activity, such as cruising, fishing, and skiing. You may well need different propellers for the
best performance in each type of activity. In any event, you should keep a spare propeller on
board at all times, along with a wrench that will fit the propeller nut, pliers, a spare nut,
and tab washer.
In switching from an aluminum to a stainless
steel propeller what pitch stainless should I go to?
The most important concern to be aware of is the correct rpm range for your engine. The
propeller pitch regulates the engine rpm. Lowering the propeller pitch (going from a 23
pitch to a 21 pitch) will increase the engine rpm, just like shifting from third gear into
first gear. Increasing the pitch (23 pitch to a 25 pitch) will decrease engine rpm. Most
applications will match up pitch to pitch and this is the best starting point. Changing
from Black Max aluminum to a Lazer II SS will usually decrease maximum rpm between 50 and
100 rpm and increase top speed by 2 to 3 mph. If your aluminum was operating in the mid rpm
range for your engine, the next lower pitch Lazer II propeller should be best for you.
Changing from Black Max aluminum to a High Five SS the rpm should hardly change. In most cases
when moving to a High Five from a 21" 3 blade aluminum at the top of the rpm range test at
Stingray have shown a 23" to work best. This would seem to contradict previous information.
The 23" High Five has exhaust vents, which the 19"and 21" pitch High Five props do not have.
These vents allow the 23"’ to slip at low rpm allowing the engine to make hp quicker
and to accelerate as well as the 21" without vents. In most of these cases the 23" will use
less fuel at cruise and have a faster top speed.
If I go from a 3 blade Laser II to a 5
blade High Five would the pitch remain the same?
When comparing the High Five with the Laser II of the same pitch, the rpm of the High 5 will
usually be 150 to 300 RPM higher at WOT. Blade design and diameter are two of the indicators
that will tell how one propeller will perform vs. another.
If I try a different propeller and it doesn't
perform, can I send it back?
No, we do not have an exchange program once a propeller is run on an engine, it becomes a used
propeller. We have no provision to deal with used propellers.
How should I maintain and service my
propeller?
Essential to good propeller maintenance is periodic inspection to detect even small dings, which
can lead to blade failure if not dressed or repaired. A damaged propeller, even one that only
appears slightly damaged by running through silt and sand, can significantly reduce performance
efficiency and fuel economy, and can more severely damage itself through cavitation erosion
emanating from the blades' irregular leading edges. In one test with a damaged propeller, top
speed fell more than 13%. Acceleration was off over 37%. Optimum cruise miles slowed 21%. Worse
yet, damage usually is not done to each blade uniformly and, therefore, the damage can set
up imbalance vibrations that can cause fatigue damage to other parts of the engine or drive. If
you boat in shallow or rocky waters, you will want to check your propeller more frequently for
possible damage.
Why is my stainless steel propeller
rusting?
Stainless Steel is just as its name implies -- it "stains" less than normal carbon steel. Only
the highest quality stainless steel available is used. Rust can occur under numerous
circumstances, including polluted water and galvanic corrosion. This can be caused by the boat,
environmental galvanic activity, (i.e. a marina's electrical system), and oxygen depletion
which can be caused by shutting off air to the propeller (shrink wrap or wrapping drive/prop in
plastic). Since this is a post purchase cosmetic defect and has no bearing on performance, there
is no warranty for rust. The rust can be removed with rubbing compounds. A Scotch brite pad is
OK but do not use steel wool. The propeller can be polished and sealed with a chrome
polish.
Why is my stainless steel propeller changing
color?
A stainless steel propeller that is turning white has been exposed to a high lime and or
calcium (oxidation) condition. Readily available commercial products will remove this and keep
deposits of calcium and lime away. A coating of chrome polish will help deter this formation.
Can propellers be re-pitched? If so, how
far?
The pitch on most propellers can be changed. On aluminum propellers a maximum change of one
inch of pitch up or down is recommended. Stainless steel can be changed up to two inches of
pitch, up or down. One inch of pitch equals approximately 125 rpm. Lower pitch to gain rpm,
increase pitch to lose rpm. Modifications will void the propeller warranty. The work of
individual prop shops cannot be controlled, especially when adding cup.
I have an older Stingray Powerboat. Where
do I find a propeller for it?
Mercury Marine has a
propeller guide with props for almost every boat. Mercury part # 90-850674-97 telephone
902-929-5054.
How does propeller torque produce boat
roll?
When observing from behind a boat, the propeller turns clockwise when underway with a normal
right-hand propeller. As water resists the clockwise rotating propeller, it causes the boat
to roll slightly in the opposite direction (counterclockwise) or down on the left (port) side
and up on the right (starboard) side. To offset this slight imbalance, the driver's seat is
placed on the starboard (right) side. Boats differ significantly in the degree of their
reaction to prop torque.
My engine will hit the rev limiter, and
is equipped with the standard prop as shown by Stingray. Does my boat have the wrong
prop?
The standard propeller recommended by Stingray is best for all-around performance under
average use. When we select a standard propeller, it is the one with the best combination
for top speed, cruising, skiing, etc. In other words, it is a "general use" propeller. No
one propeller can give you the maximum performance for "out of the hole" versus "top-end"
expectations; one comes at the expense of the other. The only way for you to achieve maximum
performance in both categories would be to carry two props, each designed to maximize their
respective feature.
For example, if you have a 190L with a 220 HP EFI V6 and a light load, the engine will hit
the rev limiter. Replacing the standard 23" propeller with a 25" propeller would reduce the
"general use" features of the standard prop and bias the performance to top-end only. You will
lose "out of the hole" performance or the low-end torque as it is frequently referred to. The
higher pitch 25" propeller will usually produce higher top speed, but is typically unsuitable
for adequate planing or water sports usage, particularly as your load increases.
Stingray dealers also have the opportunity at the time of order to select a different
propeller. In most cases, the dealer uses Stingray's recommendations.
Where can I find propeller
comparisons?
Trailer Boats magazine featured an article titled
Propfest 4.3 that
was based around several days of prop testing that we performed near our facility in Hartsville,
SC. The goal was to determine which props work best on a performance-oriented 4.3L sterndrive.
The test boat was none other than our Stingray 195LR. The article provides lots of prop data...on
lots of different props.
Another good source of information for prop comparisons is our
Radar Graphs
page. Select your model, type of test run, and engine (if applicable). Results will be
displayed at the bottom of the page. We've done a lot of testing and collected a lot of data, so
this should prove to be a good source of information.
