Installing a Drive Shower, Hot Boat Magazine
By Jim Wilkes
“The 45 degree pick up ports that all manufactures of drive coolers are using today, will fail to provide cooling water when the drive is trimmed outwardly. Results from the Multiport Drive Showers Test: 50 degree drop in operating temperature at all trim levels.“

Take a Cool  Shower, Dockside Magazine
By John Barr, technical writer for Boating and Dockside Magazines
“Test Results: Temperature reduction from a Summit on an Alpha I of 50 degrees (237 to 187)" ”

Shower Time, Hot Boat Magazine
By Jim Wilkes
“heat kills, adding a Drive Shower can add extra life to your outdrive.”

Cool Running
As seen in the May 2003 issue of Family and Performance Boating Magazine
“Multiport Drive Shower could save you big bucks”

Do I Need a to Cool My Drive?
As seen in Hotboat Magazine
“Others claim to be the best, independent tests proves otherwise”

Hit the Showers, Powerboat Magazine  - including a letter to the Editor by Simrek Corp.
By Jim Gorant, Powerboat Magazine
“A Bravo drive will give you hot performance--if you keep it cool.”

WAY TO COOL--As seen in Poker Runs of America Magazine
By Peter Tasler
“Simrek, for one, has an excellent track record.”

INSTALLING A DRIVE SHOWER, by Jim Wilkes

     Quick, what's the most  popular high-performance outdrive on the market today? If you guessed the MerCruiser Bravo One, give yourself a pat on the back.  During the last decade, the erstwhile Bravo dominated the market, both in sales and affordable performance.

     But there is a drawback to the Bravo drive in that high performance application, namely, the increase of temperature under heavy load performance conditions. The outdrive’s capacity for oil is minimal, holding  only about three quarts of oil to lubricate and diminish heat from the internal parts of the unit. Oil is pumped through the drive and used as a lubricating cushion, along with a heat transfer, by taking the heat out of the internal moving parts and transferring it in a splash condition to the aluminum housing. A heat transfer occurs from the outside water, which rushes by the unit and scrubs the heat from the aluminum outdrive casting. The heat is transferred from the internal components  via the oil that is splashed on the inside casting area.

     MerCruiser's original Bravo drive did not have an internal  reservoir. In the old days, the #4 Speedmasters had a transom plate that housed  a built in reservoir, which allowed for expansion of oil under heavy load conditions.  At length, MerCruiser realized that with the increase in load came an increase  of heat temperature. When the temperature increases, there is a greater expansion of oil and, thus, a greater risk of blowing seals as the pressure increases inside the enclosed housing. A fix for this problem was to put a reservoir inside the transom like they did on their race applications. The outdrive recovery system takes the expanded oil from the top, through the transfer tube (located about  2.5 inches below the top bearing cap of the drive), allowing for an air pocket to remain at the top where splash oil is produced. Once the heated and expanded  oil is in the recovery system, it will remain there until the oil temperature  has diminished and then will transfer back into the drive to maintain the proper oil level. Its very similar to what a closed cooling system does on your car radiator.  The transfer of heat is quite evident on the top bearing cap area, more so because  it is aerated oil being splashed against the aluminum housing. The gearcase is not dragging in the water like the lower unit, where the propeller is submerged in water. This is more noticeable to those who don't use drive showers. They may also notice the tremendous amount of white alkali buildup on the upper end of  the drive. This is due to splashed water hitting the top of the drive, which is hot enough to cause quick evaporation and leave hard-water particles. This is  similar to hard-water spots on your home shower, and they're just as difficult  to remove. It's not very pleasant to look at.

SOLUTION TO THE PROBLEM
      One way to cool the outdrive, as well  as prevent those unsightly alkali spots is to install a drive shower to the outdrive.  The standard drive showers have one outlet at the top that sprays water on top  of the outdrive. This splash system diminishes heat in the unit, but how much heat does it really remove? To find the answer, we turned to the Multiport Drive Shower, manufactured by Simrek Corporation of Henrietta, New York. The Multiport  Drive Shower is a stainless steel tube built with holes in the bottom and cut at a 45-degree angle. By dragging this unit off the cavitation plate, water can be forced to travel up the tube, then flow through the outlets on the top end,  flooding the outdrive. This flooding removes the temperature from the drive unit.

     HOT BOAT performed tests of the Multiport Drive Shower® on three different boats. The first was a 26 Howard Cat with a HP500 EFI package  and a stock Bravo drive with a 1:36 gear ratio. The Bravo is a sturdy and stout  unit, which we knew would hold up when we increased temperature and used large-pitched  propellers. With the combination of gear prop and engine torque, the unit is asked to do a remarkable job by keeping the heat down to a controllable minimum, which it cannot do on its own. High power and stock applications, due to increased load,  will also experience an increase of heat temperature in the outdrive. Increased load could be defined as a number of things: more people in the boat, a full fuel  tank, anchors, ice chests and other amenities that boaters like to have onboard. And increased load means more temperature in the outdrive due to the increased energy it takes to push the boat. In our tests, we found that one particular drive shower design does not lend itself to all applications. The Multiport Drive Shower® system gave us the opportunity to expand on what we believed could happen on some applications. The basic design of the drive shower is a piece of stainless steel  tube that is affixed to the cavitation plate and is bent to contour the design  of the outdrive with outlets on the top side and outlets on the side area that  dump water onto the top bearing cap and side area of the outdrive. The end that is submerged in the water has an opening cut at a 45- degree angle. After installing and testing the drive shower on the beautiful 26 Howard tunnel boat, we were surprised by the relatively minimal results. We only achieved a drop in temperature of 18  degrees in our oil, a far cry from the results we expected. After completing this  test, we spoke with Paul Kermis, president of Simrek Corporation, about our test results. He informed us that the wrong drive shower had been sent for our application, and he would immediately ship out the correct drive shower. The new drive shower, he said, would have more depth below the ventilating plate. When we began our testing, we hadn't realized there would be-or should be- different applications for different styles of boats. After all, the drives are all the same. But we  learned that the length of the tube below the cavitation plate was too short for  a tunnel boat. We didn't know that by trimming the drive out in the upper trim  areas, we created a cavitation in the drive shower that produced minimal water  pressure on top. This also became apparent when we tested and photographed a vee-bottom  application. The water comes off the vee-bottom boat differently than off a flat  pad in the center of the tunnel boat we tested.

     After receiving a replacement unit, we set out to perform a second test. Unfortunately, the 26 Howard that we used for our first test was  no longer available, having moved up north with its new owner. So we asked another  Lake Castaic area boat manufacturer to participate in our second test. High Torque Marine was receptive to our request and provided us with a 24SR with a blower  package and a stock Bravo drive (1:36 gear ratio). We then installed and tested  the new Multiport Drive Shower® designed for a tunnel boat. The replaced drive  shower was updated with a longer water pickup. When we performed the test, the oil temperature immediately dropped 32 degrees in the unit, but the unit didn't want to stabilize a temperature drop. And although the drop of 32 degrees was a tremendous improvement over the 18 degrees of the first test, it still didn't  compare to the 50-degree drop in temperature the manufacturer told us that many of their customers had achieved. Since their customers don't use the same testing equipment as HOT BOAT, We kept an open mind. After we saw that we took 32 degrees  out of the unit, we wanted to get a visualization of what was happening at the  back of the boat. While the boat was cruising at 40-45 mph, we lay over the back hatch and physically looked to see what the water was doing  as we trimmed the drive in and out. We wanted to know what was happening to the water once it was distributed through the holes on top of the drive and to find  out what kind of water pressure we could accumulate (as well as what kind of flow we had). Interestingly, the drive shower with the 45-degree-angle cut had water  pressure, but it wasn't impressive. It was then that we decided we would put on a Gaffrig water pressure gauge donated to us by Livorsi Marine.

     As we continued to lie over the back hatch, we saw that the water came out the exit holes on the top of the drive and hit the drive. Then  it appeared that the water recoiled. It would be like taking a garden hose, making  a pointed spray and putting it close to the ground: The water hits the ground  and rebounds upward. With the forward movement of the boat, we were not getting  any extra water running down the side of the drive from the top, which did not provide the amount of cooling we were looking for.

    Once again, I discussed our results with Paul Kermis. Based  on my observations, I suggested that instead of having the shower drive pickup  area cut at a 45 degree angle, we might add a solid tube (cap) with a hole just in the frontal area. Then, when we trimmed the drive out, we could still get the same amount of water pressure without creating a cavitation effect on the driveshaft. Paul agreed and set out to make the modification. We would need to test the Multiport  Drive Shower again.

DRIVE SHOWER MOD RESULTS
     When we added the cap to the end of the drive shower pickup and took the boat out for another test run, the first thing we noticed was the stabilization of the oil temperature while in cruise mode. We noticed  that at all rpm ranges, there would be an increase, yet the oil temperature stabilized within one degree. The consistent temperature was an improvement in itself. We were unable to do this with the stock unit with the 45 degree cut on the water pickup. On our prior test, when we cruised at 3,500 rpm, the temperature would fluctuate up one or two degrees. The longer we ran, the more it fluctuated. After this test, we repeated the process of watching over the back of the boat to see what the increase of water pressure would be. It was incredible, the pressure  increased about 75%. There was water everywhere. It was running over and around  the drive. And with the better water flow, we realized stabilization of temperature. As we increased the rpm, we found that the drive shower substantially dropped the temperature. We were able to take 43 degrees of oil temperature from the baseline of our tunnel boat. This was 43 degrees at 100 mph. Steve from High Torque  Marine suggested that increasing the rpm in 500 rpm increments through the whole test, reaching 4,000 rpm and 80 mph, then stopping and increasing to 4,500 rpm,  then to 5,000 rpm and eventually reaching 100 mph, was hard on the unit. But all  through the tests, the decrease of 43 degrees remained and stabilized under load  conditions.

FROM TUNNEL TO VEE
     Pleased with our testing results on the tunnel  boat, our next test of the drive shower was a vee-bottom. We wanted to see if we could reach the 50 degree decrease Simrek said others had reached. Simrek also  advised that the majority of the boats tested with these results were vee-bottoms. We took a 25 Sonic vee with a stock big block and Bravo drive (1:50 gear ratio)  and duplicated the test. We followed the same procedure as before: testing the  boat without the drive shower and establishing a baseline temperature. We did two different tests, one with the stock drive shower and one with the tip extension. The stock drive shower on the vee-bottom had a definite and positive effect compared  to the test on the tunnel boat. It took out over 40 degrees in the cruising mode. When we tested the vee-bottom with the tip extension, we took out 48.2 degrees,  but we still didn't reach the 50 degrees we were looking for. We felt the 48.2  degrees was as close as we would get with HOT BOAT's test equipment. Although  we didn't get a decrease of 50 degrees when using the extension tip, we did experience the same stabilization as in the tunnel boat. Our tests seemed to indicate that the new tip design worked better for the boats we tested than the 45 degree  angle cut-type tip. This is not to say that all boats running the 45-degree-angle  tip won't have good results; it simply means the boats we tested did better with a different tip design, including consistent stabilization in the cruising mode. As I stated before, this is an improvement in itself.  Simrek Corporation manufactures two different styles of drive showers, or halos. The one we tested  was the Summit design. It has seven dump ports: three on top and two on each side.  Simrek also offers a performance model, which has eleven dumps (three on the front and four on each side). The Summit design, which fits most applications of standard drives and steering systems, works extremely well. We were able to get a temperature decrease of 48.2 degrees, which was very close to the decrease stated by the manufacturer. Being able to take out almost  50 degrees is nothing short of remarkable. This means that the oil doesn't break  down as fast. Anytime we can take heat out of a product, under load conditions, we're going to extend the life of the product. Heat is death. The Multiport Drive  Shower works as well as it's advertised. But, in my opinion, one size does not  fit all. You can run into problems on tunnel boats if the depth of the unit is not correct or the water pickup hole is not in the right location. The majority  of the drives do not run a temperature gauge, so a user may not know if they're getting the full benefit of the drive shower.

    The next test we'll be doing will include the modification for a pressure gauge so we can put different tips on the bottom of the unit. This will enable us to see how much pressure we actually gain and how much temperature  drops off by trimming the drive out to the full maximum as we attempt to air out  the boat and achieve maximum speed. We are looking forward to doing these modifications,  which, in the end, will benefit all those who are looking for ways to improve  the running of their boat.

Reprinted with permission from Hot Boat Magazine
This article by Jim Wilkes appeared  in the April 2000 issue of Hot  Boat
Magazine. The pictures that accompany the article have been removed in order to
save space, though the content remains unaltered. Please refer to the magazine
for the article as it was published in its entirety.

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"TAKE  A COOL SHOWER," by John Barr

     What would you think of a product that could save your  boating vacation and thousands of dollars in the long run. No, were not talking  about investing in hi-tech stocks. We're talking about a remarkable product that  can be installed in minutes and is maintenance free.

     Most skippers are well aware that sterndrives take a lot  of abuse. Operating in the most hostile environment known to man and in outrageous conditions, they are subjected to high torque loads for hours on end. Just imagine  the loads and forces involved when a drive comes out of the water and unloads,  then plunges back into the water where the prop bites again, occurring over and  over as in racing conditions. Ah, you may say to yourself, that's racing.

     But think what happens to the drive on your own cruiser.  First off, to get your vessel on plane you're putting 300 hp and 250 ft lbs. of  torque through a 90 degree turn down a shaft to another 90 degree turn out to the prop. Then you cruise for hours with the hottest part of the drive, the bearing  cap, out of the water.  Hot exhaust is going through the drive with only 3 quarts of oil to cool it.  Like some kind of torture test you plunge the drive back into cold water as you come off of plane. To say that these drives  are an engineering marvel is certainty an understatement, but when you consider that this torture test occurs over and over on a given weekend, it's an absolute  miracle they survive at all.

Hot Stuff
     With all this considered, the greatest enemy  of the modern sterndrives is heat. Most stem drives manufacturers are aware of this problem and have developed special lubricants to combat the effects of heat and the resulting break down of lubrication protection. Even so, drives still  fail. So the logical conclusion is that if we can control the heat, our drives should last much longer.  The problem is twofold - (1) the heat produced by the drive and (2) the sudden immersion of the drive into cold water as you  come off of plane. The cast aluminum alloy which is used in the modern stern drive does not respond favorably to the expansion and rapid contraction caused when  a super hot drive is plunged into cool water. This thermal shock condition is especially prevalent in high performance applications where demands on the drive are pushed to the limit. Indicators that your drive is operating on the edge are  a white chalky deposit on the top half of the drive housing or steam generated off the transom area each time the vessel comes off plane.

Solutions
     There is a simple affordable solution. It's a drive shower. Drive showers have been around for decades and are utilized with  great success on everything from houseboats to high performance off shore racing  boats.  The operation is simplicity at its best. The drive shower routes cool water from below the cavitation plate up to the upper bearing cap where the  majority of the friction or heat is generated. By reducing the temperature of the drive it further reduces the possibility of foaming and thermal breakdown  of the oil which will certainly lead to drive failure. Easy to install, this product  could add years to the life to your sterndrives.

Unique Design
     The Dockside Test Team has tested and used drive showers for years, but now there's a new twist.  Drive showers on the market today all use one intake and a delivery tube that  picks up raw water from below the cavitation plate and dumps cool water on the drive. These showers are simple, very efficient and effective, and our own tests  have shown that they can reduce oil temperature as much as 30 degrees under most conditions.

     Recently we discovered a new drive shower that takes  this simple process and doubles its effectiveness.  The Summit and the new Halo design drive showers by Simrek Corp. expand the theory that if one is good,  two has got to be twice as good. Their unique design utilizes two intake ports for more water volume and up to eleven dump ports for more uniform distribution  on the top and sides of the drive. By using a more even distribution of the cooling  water and more water volume, in theory the drive should run cooler than a drive utilizing the traditionally designed drive shower.

Putting it to the Test
     Since the test team's 300 SeaRay was not equipped with drive showers and we were experiencing symptoms which would indicate drive  overheating, we were excited to test the new Summit drive showers. These new showers  are manufactured of polished 316 stainless steel and come complete with top quality stainless hardware and first class instructions and templates.

     Our vessel is equipped with twin 5.7 liter MerCruiser Alpha 11 drives. First, we temporarily installed our Gear Smart temperature sending unit on the- port drive and at the same time made certain the oil level was correct. We then cruised out past the breakwater until the drive was up to operating temperature. We made two wide open throttle runs in opposite directions to establish our base line. The results of this test recorded a peak drive temperature of 218 to 237 degrees Fahrenheit. With our base line established, we installed the new Summit drive shower. Although our vessel was in the water we were able to install the shower in approximately 30 minutes. Installation was simple and straight forward and could be performed by any skipper with average mechanical ability. Be certain  that you use the template supplied by the manufacturer before drilling your cavitation plate and check it twice. One important word of caution: Since our vessel was  in the water, we used a 9 volt cord less drill when performing this installation. By all means do not use a 110 volt drill near the water. Injury or death from electrical shock can occur.

     After the installation we duplicated the first test.  To our amazement, the peak temperatures had dropped to 187 degrees. This is a drop of 50 degrees and well within the drive's, and our, comfort zone. We were so amazed that we performed the test again, just to be sure. Again the temperature  had a significant drop. Though not as much of a drop as in the first test, it  was a considerable drop all the same. in speaking with an engineer he stated that  the reason we did not experience the same amount of drop was undoubtedly because  of a phenomena called heat saturation.

Seeing is Believing
     We were believers and installed the second Summit drive shower on our starboard drive. since we experienced such a significant drop  in temperature over the conventionally designed shower we can conclude that Simrek's  theory of two being better than one is right on the money.  But we're not the only ones convinced by Simrek's technology. The Multiport Drive Showers® have  been tested by and are now original equipment on Carrera Boats, Fountain Powerboats,  and Talon Marine Boats.

They are also used by US Customs on their high-performance drug interdiction vessels.  Sure glad to see that Uncle Sam finally got something right. 

     Summit Multiport Drive Showers® are available for all Alpha and Bravo sterndrives including those equipped with Imco, Latham and other external steering systems. The new Halo Design is for Bravo sterndrives equipped with stabilizers or external steering systems that bolt to the top of the bearing  cap.

Simrek Corporation 137 Pacer Drive Henrietta, NY 14467 716-334-0531

The Summit Model can be purchased from the manufacturer for $99.95 and the Halo  Design for $119.95.

Multiport Drive Shower® is a registered trademark of Simrek Corporation.

Reprinted with permission from Dockside - August, 1999.

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Hot  Boat Magazine 04/97 Hill Propeller Drive Shower

     The drive shower featured in this article from Hot  Boat magazine utilizes a single port intake and a single port output  directed at the center of the bearing cap. The testing showed a 31 degree Fahrenheit  drop (221 down to 190) at 4650 rpm. The SIMREK 'Summit' Multiport Drive Shower® utilizes two intake ports and seven strategically placed output ports; three on  the top of the bearing cap and two on each side of the housing. Twice the volume of water being delivered to seven different targets. Testing  done by a drug enforcement agency of the United States government showed a  50 degree drop in oil temperature (190 to the gauge lower limit of 140) with the use of a Multiport Drive Shower® by Simrek.

"SHOWER TIME,"  a review by Jim Wilkes.

    Proper operating oil temperatures in both the engine and outdrive  are crucial for long life.  Boil the oil in either unit, and certain death will soon follow.  Today’s engines have a recirculating water pump installed,  along with a thermostat to maintain correct engine block temperature.  Losing  control of the cooling system on an engine can be catastrophic.  Not only can you burn the rubber hoses on the engine, you can boil the engine oil as well.

       The cooling system, along with an oil cooler installed on most newer higher-performance I/O  packages, are used to control engine life.   The I/O engine packages of today have alarms on both the cooling system and on the oil system.  The  cooling system alarm will sound if you have an overheating condition, and the same alarm will sound if you lose oil pressure.  This alarm system also has a sensor in the drive oil reservoir that will sound if you run low on outdrive  oil.

    Most stock high-performance  boats built today do not monitor engine oil temperature, but those in the know  can read the oil pressure gauge and tell by a drop in pressure that the oil is warm.  The next time you run your boat, take a reading of the oil pressure while your engine is cold, and then take a second reading after you have run your  boat for 20 minutes.  You’ll find about a ten-pound drop in pressure.   For the small number of boats that have an oil temperature monitoring system on  board, there are less boats that have a means of monitoring outdrive oil temperature.

    For some years now, high-performance boaters have been installing what has become commonly called “Drive Shower” outdrives.   The Drive Shower feeds unheated raw water to the top of the outdrive bearing cap area by means of a tube or hose from the cavitation plate  area to the top of the bearing cap.  The question is, how well do these after-market showers work?

    For this test, Hot Boat went to Hill Propellers in Santa Ana, California, to test their  Drive Shower.  We explained our goal: to determine how much temperature decrease would be achieved when a Hill-manufactured Drive Shower was installed.  Joel  Bronson, owner of Hill Propellers, offered his test data on the outcome from his testing of the Drive Shower.    After perusing this information, we took a new Drive Shower (for a Bravo drive) back to Wilkes Marine for installation.   The Shower was inspected by Wilkes Marine’s lead technician, Brian Wilson,  and installed.

    The Drive Shower was made from seamless 303 stainless-steel tubing with a wall thickness of .039.  After  installing, we then removed the Shower for our test boat: a 23-foot open-bow Cougar  with MerCruiser’s 454 Magnum EFI Bravo One package as power.  (The reason  for removing the Drive Shower was to set a baseline on temperature without the Shower unit installed.)  Our means of monitoring the drive oil temperature was by installing a Consolidated Electronics Inc.   Gear Smart temperature  sensoring unit - a “one off” digital readout unit built especially for Hot Boat.  The normal Gear Smart unit uses a VDO gauge for readout.  The Gear Smart sensor unit replaces the top vent plug on the Bravo drive.

    The basic line information started with the surface water temperature at 79 degrees, along with an ambient air temperature  of 88 degrees.  The next piece of information came from running the boat. At idle, while in gear (700 rpm) indicated on the boat’s tachometer, the  temperature reading was 110.6 degrees.   Running the boat for ten minutes  to warm up all systems to their normal operating range, a full throttle run was made; 4,650 rpm was indicated and was held for approximately five miles.   The drive temperature recorded at the end of the run was 220.9 degrees.   A second test was run under the same conditions, and the temperature achieved was 220.7.

    Our Cougar was then trailered  as the Hill Marine Drive Shower was installed.  The test was duplicated,  with the same idle temperature recorded at 110.6.  With the engine oil warm and the engine temperature already in the normal operating zone, no additional warm-up was needed except for idling out of the 5-mile zone.   The same top rpm was achieved (4,650), but with the Drive Shower installed, the oil temperature in the drive dropped 31.3 degrees.  The top rpm running temperature dropped down to 189.6. A second test was run under the identical conditions, with an oil  temperature drop of 31.0 degrees.

    The Drive Shower is not a substitute for annual outdrive maintenance, but knowing that “heat kills,” adding a Drive Shower can add extra life to your outdrive.

This article appeared in HOT BOAT - April 1997, pp. 114-115.

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Cool Runnings
FAMILY & PERFORMANCE BOATING May 2003 issue
This Multiport Drive Shower could save you big bucks:

What would you think of a product that could save your boating vacation and thousand of dollars to boot? We’re talking about a remarkable product that can be installed in minutes by anyone with average mechanical skills, and best of all, it’s maintenance free.

Most skippers are well aware that stern drives take a lot of abuse, since they operate in extreme conditions and in one of the most hostile environments known to man. Think what happens on any given weekend to the stern drive on your own sport boat First, just to get your vessel on plane, you’re putting 330 hp and 300+ lb-ft of torque through a 90-degree turn and down a shaft to another 90- degree turn out to the prop. Then you cruise for hours with the hottest part of the drive, the upper gearcase, out of the water. And to top it off, you’ve got hot exhaust going through the drive with only 3 quarts of oil to cool it. Then, as if in some outrageous torture test, you plunge the hot drive back into cold water as you cone off plane. To say that a stern drive is an engineering marvel is an understatement. When you consider that this “torture test” occurs over and over again on a given weekend, it’s a miracle they survive at all,

Hot Stuff
With all things considered the greatest enemy of the modern stern drive is heat. Most stern drive manufacturers are well aware of this problem and have developed special lubricants to combat the effects of heat and the resulting thermal breakdown of the lubrication. Even so, drives still fail. The logical conclusion is that if we can control the heat, our drives should last much longer and our boating adventures should be trouble-free.

But the problem is twofold: (1) the heat produced by the drive, and (2) the sudden immersion of the drive into cold water as you come off plane. The cast aluminum alloy that is used in the modern stern drive does not respond favorably to the expansion and rapid contraction caused when a super-hot drive is plunged into cool water. This thermal shock condition is especial prevalent in high-performance applications where demands on the drive are pushed to the limit. A positive indicator that your drive is operating on the ragged edge is a white, chalky deposit on the top half of the upper gearcase or steam generated off the transom area each time the vessel comes off plane, And, of course, smelly, burned or black drive lubricant discovered at scheduled service intervals.

Solutions
There is a simple and afford able solution. It’s a drive shower. Drive showers have been around for decades and are utilized with great success on everything from houseboats to high—performance offshore boats. Their operation is simplicity at its best. The drive shower routes cool water from below the cavitation plate up to the upper bearing cap where the majority of the friction and heat is generated. Reducing the temperature of the drive further reduces the possibility of foaming and thermal breakdown of the oil, which will certainly lead to drive failure. Easy to install, a drive shower could add years the life of your stern drive.

Over the years, we have tested a variety of drive showers. Some worked well, while others were questionable. Traditional drive showers on the market today all use one in take and delivery tube to deliver cool water to the top of the drive while the vessel is in motion. These showers are simple and effective. Our own tests have shown that they can reduce drive oil temperatures as much as 30 degrees under most conditions.

Recently, however, we discovered a new drive shower that takes this simple process and doubles its effectiveness, the Summit and the new Halo drive showers by Simrek Corp. expand on the theory that if one is good, two have to be twice as good. Their unique design utilizes two intake ports for more water volume and up to11 dump ports for uniform distribution of cooling water on the top and sides of the drive. By using even distribution of the cooling water and more water volume, in theory the drive should run cooler than a drive utilizing the traditional design. In theory, Simrek’s new design should be twice as effective, but being the skeptics that we are, we decided to put the Summit and the Halo to the test in three different, applications on three different styles of drives.

Putting It To The Test
To assure that all our testing was conducted in a fair and impartial manner and eliminating most variables, each drive was prepared for testing in the following manner: The drive was drained and refilled with MerCruiser High-Performance Gear Lube+ ( PH 92-802854A 1} according to Mercury’s instructions. For all tests, the drive was brought to operating temperatures above 100 degrees F., and all trim settings were identical throughout the tests. All tests were conducted with two persons aboard and approximately three-quarters fuel load. On each test we first established and recorded baseline temperature. The tests consisted of a 3-mile run at 4100 rpm in both directions. On both test days the ambient temperature was 97 to 101 degrees and the water temperature was 85 to 87 degrees. All data were recorded using OPS, Stalker radar and a Consolidated Gear Smart analog drive temperature sensor.

First Off The Dock
Our first test was on a 28- foot Donzi sport boat equipped with twin 5.7-liter MerCruiser and Alpha I Gen II drives. The vessel was manifesting symptoms that would indicate the drives were overheating, including white deposits on the upper gearcase. We first brought the drives up to operating temperature and made the two runs according to our protocol to establish a baseline, recording peak drive temperatures of 218 to 241 degrees F. on both drives.

With our baseline established we installed the Summit drive showers. Even with the vessel in the water, we were able to install the showers in approximately 30 minutes. Installation was simple and straightforward and could be performed by any skipper with average mechanical ability. Be certain you use the template supplied by the manufacturer before drilling your cavitation pate and check it twice. One Important word of caution: Since our vessel was in the water during installation, we used a 9-volt cordless drill when drilling the required mounting holes. By all means, do not use a 110-volt drill near the water. Injury or death from electrical shock can occur.

After the installation, we duplicated the original test. To our amazement, the peak drive temperatures had now dropped to 187 to 190 degrees. This is a drop of approximately 50 degrees and well within the drive’s and our, comfort zone. We were so amazed that we performed the test again just to be sure. Again, the temperature had a significant drop. Although not as much of a drop as in the first test it was a considerable drop all the same. In speaking with a MerCruiser engineer, he said the reason we did not experience the same amount of drop was undoubtedly because of a common phenomenon called heat saturation.

Seeing is Believing
For our second test, we used a Formula 26-foot deep-V sport boat equipped with a single MerCruiser 7.4 LX MPF with a Bravo Ill drive with a 1.81 gear ratio. The vessel’s approximate weight was 4,700 lbs. On our baseline run, we recorded a high temperature of 273 degrees on the south run and 271 degrees on the north run. After installing the Halo Multiport drive shower and stabilizing the drive temperature, we conducted the same protocol used in the first test series. Test results were: On the north run, we recorded a peak temperature of 221 degrees and on the south run we recorded a peak temperature of 219 degrees.

On both test protocols, we experienced approximately a 47- to 52-degree reduction in drive temperature. To say the least we were pleased with the results.

Twin Bravo One Drives
Our third and final test vessel was a 32-foot Baja powered by stock MerCruiser 502s and twin Bravo One drives. Again, after establishing baseline temperatures, we installed the original Summit on the port drive and the Halo design on the starboard drive. (These drives were counter-rotating, and the starboard drive had a temperature reading of approximately 4 degrees higher than the port drive.) We then followed the same protocol used in the original test. To our astonishment, we found that we had recorded an 8- to 10-degree further drop in temperature in the drive equipped with the Halo drive shower over the drive equipped with the Summit shower, after taking into account the drive temperature differential. But what is noteworthy is that although the temperature in the Summit-equipped drive did record a slight temperature rise over time (2 to 4 degrees) due to what we again suspect was heat saturation, the drive equipped with the Halo unit did not experience the same phenomena. Needless to say, we were again impressed with the results.

We are not the only ones impressed by Simrek’s technology. The Multiport drive showers have been tested by and are now original equipment on many boats. They are also used by U.S. Customs on its high-performance drug interdiction vessels.

The Bottom Line
Both Simrek’s Summit and Halo drive showers work to control a stern drive’s worst enemy: heat. Simrek’s product is manufactured of polished stainless steel with high-quality hardware. We found Simrek’s customer service to be very responsive to our questions and inquiries, and its installation instructions were easily understood with excellent templates.

Multiport drive showers are available for all Alpha and Bravo stern drives, including those equipped with IMCO, Latham and other external steering systems. The new Halo design is for Bravo stern drives equipped with stabilizers or external steering systems that bolt to the top of the bearing cap. Simrek has also developed a new patented water pick-up that assures positive water flow and volume regard less of trim angle or bottom design, including cats and air— entrapment hulls. Product Profile: Simrek Corporation Dept. FPB, 137 Pacer Dr., Henrietta, NY 14467, (585) 334 - 0531

Website: driveshowers.com

Reprinted with permission from:
FAMILY & PERFORMANCE BOATING May 2003 issue, pages 67 to 69

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DO I NEED TO COOL MY DRIVE?
Published  in HOT BOAT, May 2000:

     Pleasure boats  and performance boats alike: Published test results show that some stern drives operate in excess of 350 degrees. The white chalky deposit means that the outside  casing of your drive is running hot enough to boil off the water that splashes onto it. This boiling process turns the water into steam and leaves the mineral  deposits behind to bake onto the drive. The hotter the drive, the more deposits are collected, and the harder they are to remove. Keep in mind that however hot the casing is, the oil and the components inside, are much hotter. Other signs that your drive may be running too hot, is a discoloration of the paint, or a  cloud of steam appearing from the transom area every time your boat comes off plane. Unless you have through hull exhaust, what you are seeing is not exhaust, it is 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.

Others claim to be the best -  independent tests proves otherwise

The Multiport Drive Shower®

     This unique design differs from other drive cooling systems by utilizing two intake ports for a greater water volume, and either seven or eleven dump ports, strategically placed for a more uniform distribution. All components are made of 316 stainless steel, carry a full year warranty, and are guaranteed to fit your application.
     Testing done by The U.S. Customs Service on a 42' Fountain, found that the Summit Multiport Drive Shower® lowered the drive operating temperature by 50 degrees. Similar tests were conducted by John Barr of Dockside Magazine  on a 300 Sea Ray. He published the same results in the 08/99 issue. He also learned that the Halo had provided an additional 8 degrees of cooling over the Summit. Jim Wilkes, a technical writer for Hot Boat Magazine, performed extensive testing,  and published similar findings in an article in the 02/00  issue. He also discovered that a tunnel hull, or any boat with a high "X' dimension, will lift the drive, along with the pick-up ports of the drive cooler, out of the water  at higher speeds. To solve this problem, Simrek is now offering longer pick-up  ports for these types of boats. Members of Team Lazzara conducted a side by side  comparison of an lmco Power Shower and a Halo Multiport Drive Shower® on their F2 race boat. They found the Multiport system had cooled the drive oil by an additional 15 to 20 degrees.

WHY PICK-UP PORTS CAN FAIL
      

     In an attempt to minimize costs, drive cooling system manufacturers simply cut the end of the  pick-up tube at a 45 degree angle. These systems might supply sufficient cooling  water for pleasure boating, but not performance boating. As you trim the drive outwardly, water contacts the back wall of these 45 degree pick-up ports and is deflected up the tube at a decreasing rate. Independent testing has proven that  boats requiring the drive to be trimmed to near or past vertical in order to achieve maximum performance, will cause the drive cooling system to eventually fail. Propeller spray alone did not provide the water volumes necessary to cool the drive.

New Optional Pick-up Ports

     To alleviate this problem, Simrek has designed, tested, and patented a new 90 degree pick-up port that forces the water to enter the tube at any trim level.  These new patented tips are now being offered exclusively to Multiport Drive Shower® customers as an option, in sets of two. They come in two lengths, a standard length  for V-hulls and a longer length for stepped V-hulls and tunnel hulls.

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DRIVESHOWERS · BY Jim Gorant
POWERBOAT Magazine August 2000 page 38

After receiving the following e-mail from the author, we at Simrek decided that the article did  not warrant any compensation and decided to simply remove it.  We are very shocked the author would even hint at a compensation issue, much less outright ask for it. However our response to the original article is below their email. You’ll still find the original article in the archives at Powerboat Magazine.

The Following is our response to the article in a letter to the editor
(PUBLISHED BY POWERBOAT MAGAZINE DECEMBER 2000 PAGE 16 TITLED  SHOWER POWER)

Dear Jo Stich;

After reviewing the article, I have come to the conclusion that the engine builder that was used as the main source of information was not familiar with  our systems, (which has been referred to as "The next Generation Drive Cooler").  Your article is correct as long as you do not consider my product as grouped in with the rest. Nonbiased is good, but accurate is better. As you suggested, I have attached a 'letter to the editor'. I hope that you will help me by publishing it soon.

Dear Editor of Powerboat Magazine;

For the past two years Simrek Corp. has been manufacturing the Multiport Drive Shower® that your magazine pictured in the August issue within the article entitled "Hit the Showers". Though I do concur with the author that MerCruiser's little  secret about their heat build up problem is pretty much out of the bag, I also  found that your source of information, with respect to cooling them, was outdated.

The article stated, "Some (drive showers) dribble a spray over the top while others encapsulate the upper end of the drive and thoroughly douse it." I thought that it was rather humorous that the author repeatedly referred to the amount of water that a system like ours utilizes as "dribbling" and/or "sprinkling" when  simple math proves that our system, with it's two pick-up ports, will supply water  at a rate of 17.5 gals./min. with the boat traveling at 40 mph. That's far from  dribbling!

The article also read, "both styles seem to work equally well". Testing of our system was done by two other magazines. They recently published their findings  that the Multiport Drive Shower® will out perform the competition by nearly twice  the cooling capabilities. Independent source testing has concluded that our Summit model will cool the drive by 50 degrees and our Halo model by 55 to 60 degrees.  All of the other systems, regardless of their configuration, have only one pick-up port and will cool the drive by only 25 to 30 degrees.

Through extensive testing, it also became obvious to us that the pick-up ports that are found on all of the other drive cooling systems, and have been for years,  can fail at higher trim levels when they are needed the most. We have redesigned our system with a patented 90 degree pick-up port that continues to cool the drive at all trim levels.

We at Simrek are proud of the fact that a boat owner can spend well over twice as much for another drive cooling system that will only cool their drive by half as much. We have by far the best drive cooling system on the market today, and  to back up these claims we have posted all of the documented test results from  the outside testing firms on our web site at www.driveshowers.com.

I just thought that your readers would appreciate this information before they spend their money on an outdated and inferior system.

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WAY TO COOL by Peter Tasler

For performance boats, drive showers have become a popular aftermarket add-on. A few decades ago, if you asked a performance boater if he or she had ever heard of - let alone, installed -a drive shower on their boat, you might have raised a quizzical smile. Surely, you'd have the person in question scratching their head, no clue as to what the heck you were talking about. Well, times have changed.

Unlike those magnetic-type devices that promise incredible fuel savings, drive showers have successfully made the transition to respectability. Several leading manufacturers such as Simrek and Imco make and sell drive showers. Performance boat builders such as Cigarette and Fountain install drive showers on their boats. Performance boat owners who have had drive showers installed as an aftermarket accessory are convinced that they have done the right thing. Question is, if drive showers are that vital, why would drive builders not install them as standard equipment? Poker Runs America wanted to know more. A quick phone call to Mercury  Racing provided additional insight.

One of the main reasons they do not install showers as OEM equipment, we were  informed, was that Mercury Racing designs its drives to handle a certain horsepower range and the temperatures associated within that range, in typical -boating environments.

Paul Kermis, president of Simrek Corporation, based in Henrietta, NY, is one of the leading exponents of the need to install drive showers.

"We've had people come to us, complaining about white chalky deposits on the top half of their stern drive. Basically, this means that the casing of the drive is hot enough to boil off the water splashed onto it. This results in mineral deposits baked onto the drive. The higher the heat, the more deposits. Paint discoloration is another sign that your drive is running too hot, so is a cloud of steam you'll see every time your boat comes off plane. The extreme shift in temperature, from  hot to cool, can damage an engine's metal components. It's especially harmful to aluminum, if the range is extreme."

Casing aside, drive components do run much hotter. Test results show that some stern drives operate higher than 350 degrees Fahrenheit.

Enter the drive shower, a device that distributes a continuous supply of cool  water to a stern drive's upper half. Test results speak for themselves. The cooling generated by drive showers can reportedly double the bearing and service life of the drive oil by lowering an operating temperature of 220 to 350 degrees Fahrenheit  by 30 percent. Kermis explains that this reduction in heat prevents oil foaming, a primary cause of oil breakdown which can lead to drive failure.

"It also reduces the thermal shock that occurs when the hot drive is plunged into cool water every time the boat comes off plane. This applies to nearly every boat, but it's especially  prevalent in high performance applications."

Thermal shock, incidentally, is a condition that exists when metal, for example, is heated up and then cooled quickly, resulting in rapid expansion and contraction. Drive casings are made of cast aluminum that can develop small stress cracks if frequently subjected to thermal shock. Bearings and gears inside the drive could  also undergo excess wear.

There are several designs of drive showers, most target the top bearing cap. One is a solid tube design with and without a bearing cap plate. The sold tube system sprays water at the top surface of the drive from a 1/2 inch diameter tube located at a 90-degree angle to the top the drive, about a 1/2 inch away. The  flexible tube system with an optional bearing cap plate directs water at the top bearing cap at almost a 180-degree angle, causing the water to skip over the top of the drive.

The Simrek Multiport system makes use of two pick-up ports, targeting the top  and two sides of the drive, Test reports indicate that drive showers are well worth the price. Installation is easy. Simrek boasts it takes only 15 minutes  or so to make their system operational, others may take longer. Whatever the case,  or whatever system you decide to buy, the fact that drive showers do their job well is best said by the individuals who actually have benefited. Simrek, for one, has an excellent track record. Users such as High Torque Marine, Advantage  Marine, Twisted Styx (and chyx) race teams as well as the U.S. Customs Service  are believers.

Dennis Lozito, president of Oakland Park, Florida-based Community Auto Marine  concurs.

"We had a 1999 45-foot Wellcraft Excalibur with signs of serious overheated  drives. We installed a Halo drive showers and Gaffrig temperature gauges. We also  changed the drive oil to Amzoil Synthetic Gear Lube. We tested the boat with the drive shower eliminated on the starboard drive and found as follows:

Each test was run over a three mile area. Your drive showers have solved the problem. There is no more discoloration on the top of the drives."

CONCLUSION

There's no doubt that drive showers reduce drive temperatures. We don't really have detailed long-term tests to associate temperature reduction with drive component life and reliability, but we do know for a fact that there is no good reason to add heat to drives and lots of reasons to keep them cooler. Drive showers are not expensive, easy to install and an advantageous preventive measure. As always,  the final decision is up to you. 

This article by Peter Tasler appeared in the Volume 4 Number 2 Year 2000 issue of Poker Runs America Magazine. The pictures that accompany the article have been removed in order to save space, though the content remains unaltered. Please refer to the magazine for the article as it was published in its entirety

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