|
1. Do I need a
drive shower?
2. What does a drive shower do?
3. What is thermal shock?
4. Why a Multiport Drive Shower®?
5. What about the other drive showers
6. What kind of temperature reduction will I
get with a Simrek Multiport Drive Shower®?
7. Why doesn't MerCruiser put them on their
drives as standard equipment?
8. Do I need the 90 Degree Pick-up Ports?
9. Will the Multiport Drive Shower® cause drag and
slow my boat down?
10. Do the stock bolts on the drive
require a special wrench?
11. I have Latham (or Imco) Steering and I want to
install a Halo. How do I remove the stud?
12. Will a drive shower void my warranty?
13. What about Drive Coolers that target the top
cap but also force the water down the sides?”
1. Do I need a drive shower?
According to the certified MerCruiser Master Technician
that Simrek contacted, "every boat should have a drive
shower." There are two obvious signs that your drive may be
running TOO HOT:
A. If there is a continuous need to remove a white
chalky deposit from the top half of the stern drive. The
white chalky deposit means that the outside casing of your
drive is running hot enough to boil off the water that is
splashed onto it. This boiling process turns the water
into steam and leaves the mineral deposits behind to bake
onto your drive. The hotter the drive, the more deposits
are collected, and they harder they are to remove.
B. Other signs that your drive may be running too hot include
paint discoloration, or a cloud of steam that appears every time
your boat comes off plane. Unless you have opened
through hull exhaust, what you are seeing is not exhaust; it's
the steam that is generated when a hot drive is plunged into
cool water. This process of heating and rapid cooling is
known as thermal shock and can be detrimental to metal
components, especially aluminum, if the range is extreme
enough. Keep in mind that however hot the casing is, the
components inside are running much hotter. Published test
results show that some stern drives components operate in excess
of 350 degrees. If you are experiencing any or all
of the above conditions, your drive is probably operating over
250 degrees. For the same reasons that automotive
engineers established approximately 200 degrees as an
optimum operating temperature for their engines, most marine
experts agree that this also holds true for stern drives.
Drives listed in order by operating temperatures:
(hottest)
- Bravo III (270+ degrees)
- Alpha (all) 265+ degrees
- Bravo II
- Bravo HP, XR and ZR Drives (due to their performance
applications)
- Bravo I
(coolest)
Back to top
2. What does a drive
shower do?
Drive showers distribute a continuous supply of cool
water to the top portion of the stern drive. Tests have
shown that cooling like this can double the bearing life and
service life of the drive oil by lowering an operating
temperature of 220 to 350+ degrees Fahrenheit a minimum of 30%.
It prevents oil foaming, the primary cause of oil break-down
which can lead to drive failure. It also dramatically
reduces the thermal shock that occurs when the hot drive is
plunged into cool water every time the boat comes off
plane. These conditions exist on nearly every boat, but is
especially prevalent in a high performance application where
demands on the drive are pushed to the limit. Under
normal operating temperatures, most manufactures recommend
that the oil in their drives be changed every 50 hours.
For some, 50 hours can be a few week's worth of use.
Back to top
3. What is thermal
shock?
This is a condition that exists when metal, or other
materials, are heated up and then cooled quickly.
The materials expand from the heating process and contract
rapidly when cooled. The drive casing is made of cast
aluminum which can develop small stress cracks when subjected to
thermal shock on a frequent basis. Also, the many bearings
and gears inside the drive develop excess wear from the constant
dimensional changes that occur during thermal induced
expansion and contraction.
Back to top
4. Why a Multiport
Drive Shower®?
The Simrek Multiport Drive Shower® System utilizes two
pick-up ports for twice the water volume than any other drive
cooling system available. It is also the most efficient
because it targets the top and two sides of the drive.
All the other cooling systems available target only one
surface of the drive with one dump port. Drive shower
systems that only spray water on top of the drive are less
efficient because they target the bearing cap on the top of the
drive which is over an inch thick. The sides of the drive
are less than 1/8th of an inch thick and offer much less
resistance to temperature change. They are also the only
drive cooling system to utilize the 90 Degree Pick-up Port
System.
Back to top
5. What about the
other drive showers, including knock offs that don’t require
drilling?
There are two designs of shower systems targeting the top
bearing cap. One is a solid tube design, the other
is a flexible tube design with and without a bearing cap plate.
At first glance, both would appear to cool the sides of the
drive simply because the water will run down from the top.
Consider these two conditions:
The solid tube system sprays water at the top surface of the
drive from a 1/2 inch diameter tube which is located at a 90
degree angle to the top of the drive, and about 1/2 inch away.
Try this experiment at home: turn a drinking glass up side down,
and hold it under your faucet approximately 1/2 inch away.
Now turn the faucet on full force. You will
probably find that every thing in the room is now soaking wet,
(including yourself --- sorry about that!), except the sides of
the glass are still dry. This is due to the force
and velocity that the water is under as it exits the faucet.
The same principles hold true in the case of a drive
shower.
The flexible tube system with an optional bearing cap
plate directs the water at the top bearing cap at almost a
180 degree angle. This causes the water to skip over the
top of the drive and exit out the back of the plate on to your
transom. This is a great way to wash your transom, but not
a very efficient cooling system for your drive. Try this experiment at home: turn a kettle up side down in your
drive way. (This time I promise you that you won't get wet.)
Hold a garden hose, at an angle a little more than
horizontal to the ground and about an inch away from the
kettle. Open the spray nozzle to full force.
You will probably find every thing behind the kettle is soaking
wet, but the sides of the kettle are still dry.
With the force of the water that is
traveling through a 1/2 inch diameter tube at speeds equal to
the that of the boat, it is easy to see that this water will
only go where it is aimed, and gravity will have little
influence on its path. Through the use of multiple
dump ports aimed at the top and both sides of the drive, the Simrek System delivers the cooling water under less pressure,
which allows it to spend more time in direct contact with
the side surfaces of the drive.
 |
In the recent past, there have been numerous attempts to not
only copy the design of our driveshowers, but to get around the
US Patent that was issued to us for the innovative design our 90
degree pick-up ports. This is just another one of the latest
attempts to do so. The concept of not having to drill any holes
in the anticavitation plate is appealing, but it does have its
drawbacks. When we originally designed our drive showers over 6
years ago, we utilized a Computer Assisted Design Program call
Pro-E. We explored the idea of coming up with a design that
would be mounted to the drive without drilling any holes. We ran
the stress analysis package of Pro-E against a similar
configuration to the drive shower shown above. The results told
us that the shear load produced by water flowing at just over 64
MPH. would be equal to the same force that we now use to form
the tubing into our drive showers. At just over 40 MPH, the
force produced by the water pressure is enough to deflect (flex)
a .500 inch OD X .403 ID 316 SST tube by 5.263 degrees for every
inch of unsupported tubing exposed to that water flow. It
doesn’t sound like much deflection until you start multiplying
it by 10 inches.
The Trigonometry formula goes like this: .0175 per degree per
inch. Or .0175 X 5.263 degrees X 10 inches = .921. That’s just
under an inch of deflection when 10 inches of unsupported tube
is exposed to the pressure of water that is traveling at 40 MPH.
I took you through the physics and trigonometry, in order to
show you one of the reasons we originally rejected this design.
We felt that the pick-up ports would be deflected upwardly
enough to render them unable to supply a continuous flow of
water to the top of the drive. Then when the water pressure
falls low enough, the tube would return to its original form.
Unless you were watching the shower while the boat was underway,
you would never know if it was working or not
A recent posting on EBay for one of these showers had a
description as follows: “This drive shower was purchased at the
end of 2003. After installing it onto my Bravo 1 drive and
running it twice on the lake I decided to upgrade to an IMCO XR
drive which comes with its own drive shower.” This is the
picture that accompanied the description. Notice that after
being used only twice, the tips are already bent.
6. What kind of
temperature reduction will I get with a Simrek Multiport Drive
Shower®?
Back to top
The most recent testing was done by Jim Wilkes for Hot Boat
Magazine, and published in the April 2000 issue.
Dockside magazine also tested the Summit Design and found a 50
degree drop in drive operating temperature and published
their findings in the August 1999 issue. They also did a
side by side comparison between the Summit Design and the
Halo Design and found the Halo to cool the drive by an
additional 8 to 10 degrees. Testing was also
performed by the United States Customs Service. They
found a 50 degree Fahrenheit drop in temperature.
Gene Weeks of Team Lazar did a side by side comparison
between an Imco Power Shower and a Summit Multiport Drive
Shower®, and found the Multiport system to cool the drive by an
additional 15-20 degrees over the Power Shower.
Back to top
7. Why doesn't
MerCruiser put them on their drives as standard equipment
Simrek feels that MerCruiser makes the finest stern
drives on the market, but they are in business to make a profit.
In order to incorporate a cooling system into the stern drive
they would have to make major changes to the castings that make
up the upper portion of the drive. While some changes
have been made to the internal components, the castings for both
the Alpha and Bravo uppers have not changed since they
were first introduced. Adding a cooling system would
require a major redesign of multiple castings at a substantial
cost.
MerCruiser is also in the repair parts business. There is
a term used by manufacturers called "planned obsolescence."
If a product lasts too long, there will be fewer repeat
sales or repair part sales. That is why no one sells a
light bulb that doesn't burn out eventually.
Unfortunately for Simrek, the Multiport Drive Shower® has no
planned obsolescence. We do not sell repair parts because
there is no need for repair parts.
In the article "Way to cool" that appeared in Poker Runs of
America Magazine, Editor Peter Tasler asked Mercury Racing
why they didn't install drive showers as OEM equipment? There
response was, "Mercury Racing designs its drives to handle a
certain horsepower range and the temperatures associated within
that range, in typical boating environments."
Back to top
8. Do I need the 90
Degree Pick-up Ports?
If your boat requires you to trim your drive near of past
vertical while you are performance boating, then your
drive cooler is probably not picking up any water. The
Pick-up Ports of all drive cooling systems offered today consist
of a tube mounted through the cavitation plate at a 90
degree angle and cut off at a 45 degree angle. This
means that the tube is being dragged through the water at a 90
degree angle when the drive is trimmed to vertical. When
you trim the drive out further, the tube is facing away
from the stream of water. Under these conditions the
Pick-up Ports will fail to supply the cooling system with enough
water to adequately cool the drive at a time when they are
needed the most. This is not a smart design.
When we first introduced the Multiport Drive Shower®, we thought
the problem with existing cooling systems was primarily in
the water delivery system. We addressed that issue and
have since identified the opportunity of maximizing the pick-up
system. Independent testing verified this, and because the
improvement was so great, we decided to apply for a US Patent.
The 90 Degree Pick-Up Ports that Simrek offers exclusively to
Multiport Drive Shower® customers provide a continuous supply of
cooling water at any trim level. Because the Pick-Up
Port faces forward into the stream of water going under
the cavitation plate, they scoop more water than the
conventional 45 degree ports. Instead of failing
during performance boating, they are actually at maximum
efficiency.
Back to top
9. Will the
Multiport Drive Shower® cause drag and slow my boat down?
The pick-up hole makes up the majority of the small 1/2 inch
diameter tube that is exposed under the cavitation plate.
Because the water is only being re-directed, instead of
being forced to build back pressure (as it does in the case of a
speedometer pick-up) no speed reduction will be noticed. The
Multiport Drive Shower® is used on a large number of race boats.
Race teams measure their boats speed in tenths of a mile per
hour. If the drive shower caused any loss in speed, they would
know about it and remove it without hesitation.
10. Do the stock
bolts on the drive require a special wrench?
The stock bolts on the drive can be removed with a standard 3/8
- 12 point socket.
Back to top
11. I have Latham
(or Imco) Steering and I want to install a Halo. How do I
remove the stud?
If you are installing a Halo on a drive with Latham or Imco
steering; To remove the top left stud from the drive, use a
separate nut (3/8 x 16) as a jam nut. Tighten the two nuts
together so that you can place a socket over the jam nut and
onto the original nut. Loosen both nuts at the same time.
The stud is not Loctited in, and should come out easily.
Back to top
12. Will a drive shower void my warranty?
We developed our new “No Drilling Mounting System” as a result
of MerCruiser’s new policy regarding damage to the finish on
their new drives voiding their Corrosion Warranty. When asked
about drilling holes in the drive to mount a shower, Rick Lang
at Mercury Marine replied, "If an aftermarket component causes a
failure, or in this case leads to corrosion damage... our
warranty will not cover the damage/failure". Also, for SeaCore
product "under no circumstances should the surface of the finish
be damaged or it will corrode and there will be no warranty".
Back to top
13. Coolers that
target the top cap but also force the water down the sides
If you wanted to cool a glass of water you would be better off
putting it in the freezer than in the refrigerator. The same is
true of cooling your drive, the colder the water the better. Why
would you want to pre-heat the water by first passing it over
the top bearing cap?
Anytime you force water into a chamber, as many cooler do, you
will “break its stream”. Anyone who has used a garden hose has
seen the effects of streaming. Once water has taken a shape it
has a tendency to retain that form. That’s why the water from a
hose keeps the shape and diameter of the hose until gravity or
some other force interrupts it. Once the water is inside this
chamber and is forced to exit through a hole or series of holes
or even simply by turning 90 degrees and then downward by 90
degrees, the flow has been interrupted twice. This is called
“resistance to flow” or “back pressure” and reduces the amount
of water that the system can process. The smaller the water
flow, the less efficient the system will be at cooling the drive
and if enough back pressure is created, the pick-up port may
cause enough drag to slow the boat down.
Back to top
|
