November 29, 2012
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Make Your Flatty Drive Like a Mercedes….It’s All In The Pedal!

It’s long been said that ‘necessity is the mother of invention.’  Nobody will argue with that, especially Denis Porter who hung out with his two flatbottoms at Lake San Antonio in central California.

Denis has lived his life as one of those full-throttle kind of guys as evidenced by his lengthy medical history littered with broken bones and other assorted injuries.  Whether it’s on two-wheels, four-wheels or in boats, it’s an all-or-nothing kind of existence.

But those multiple high speed indiscretions haven’t been without consequence.  Now that he’s on the plus side of sixty, Denis’ left knee doesn’t work as well as it did a couple of decades ago.  Although it still has some flexibility, its range of motion is noticeably limited.  For most people six decades old, that might not be a big deal, but for Denis it was an ever-irritating problem because as a hard-core flatbottom driver (owner of a 1979 Hondo, formerly the “Californian Shaker” drag boat, and a very nice and very fast Cole), working the all-important manual cavitation plate down-pedal was next to impossible.

For those not familiar with conventional flatbottom down-pedals, they are simply a pedal operated over-ride mechanism that lowers the cavitation plate on the transom when the driver pushes it with his left leg/foot.  What’s not apparent, however, until you sit behind the wheel of a well-horsepowered flatty is that the pedal is stiffly spring loaded requiring as much as several hundred pounds of direct human pressure to make it go down.  The reason you want to lower the cav plate is to keep the bow of the boat from launching skyward during hard acceleration.  If you attend a drag boat race, just watch the commitment area ahead of the Christmas tree lights for a demonstration.  In order to maintain control, as the driver approaches the starting line, he’ll apply pressure to the down pedal lowering the cav plate which in turn lifts the transom and lowers the bow.  If done correctly in just the right amount, when the light turns green the driver can hammer the throttle and still control the boat with a low bow angle.  Then as the boat accelerates, the driver feathers out of the down-pedal allowing the boat to free-up and take its optimum set.  Sounds simple, until you try to do it, especially with a bum knee.

“If I push hard enough on a conventional down-pedal when I’m driving, I’m afraid I’ll pop my hip out of joint,” says Denis.  “I knew there had to be a better way and I was determined to find it.”

Fortunately for Denis, he’s a master machinist, someone who thinks nothing of taking a block of billet aluminum and milling it into some exotic shape of his own design.  “I’ve got a 5,000 square foot workshop/warehouse on my property with plenty of CNC equipment to do just about anything I want,” remarks Denis.  “My company is Machine Automation Systems (MAS) which specializes in the rebuilding and repair of industrial machinery.  So taking on a simple project like making a better down-pedal system for a flatbottom didn’t seem that difficult.”

To achieve what he was looking for in the way of a power-assisted down-pedal, Denis was certain that hydraulic actuation was going to be the answer.  “I wanted something that would be fast reacting, completely adjustable, and have a huge  fail-safe margin.  It should be the last thing in the boat you ever have to worry about.”

While this article could easily evolve into a technical dissertation about hydraulics, fluid dynamics and the intricacies of CNC machining, that’s perhaps best a discussion left to another time.  Suffice it to say, Denis was successful in building a first prototype and installed it in his Hondo.  “I took the boat up to one of the Camp Far West rendezvous and just let people drive the boat and give me their honest feedback.  I knew it worked for me, but I was curious to know if other flatbottom drivers appreciated it like I did.”

At the end of the weekend, Denis reports a unanimous thumbs up from everyone who took a turn in the driver’s seat.  “They were more complimentary than I even expected,” says Denis.  “I don’t think there was one complaint.  I was pretty sure I was on to something.”

Denis’ invention works like this.  The super heavy-duty spring that delivers the necessary tension for a conventional down-pedal is eliminated entirely.  Instead, there’s a directional control valve that tells the hydraulic cylinder how much to move based upon how far the pedal is depressed.  Basically, the control valve follows what the pedal does.  Denis’ system uses a low volume pump that can be driven off the engine or V-drive via a belt or gear set.  The reason for the low volume pump is that it encourages a faster and more consistent reaction and feel on the pedal.  “About 90% of the effort to move the pedal is taken over by the hydraulics,” says Denis.  “The pedal still feels normal, but it will simply depress and lower the plate with only a fraction of the previously needed muscle-power.  In actuality, the system works quicker than you can move your leg or foot.  It’s just that responsive.  And if you take your foot off the pedal for any reason, it naturally returns to its original position.”

An additional feature of the system is that once your cavitation plate is set exactly where you want it with the turnbuckles, you never have to touch it again when you want to make a slight adjustment.  That can be done inside the boat  by simply loosening the jam nut  on the control rod and moving it forward or back depending on what adjustment is needed.  There are also some people who  have expressed concern about what will happen if the hydraulic pump fails and the unit is no longer assisted.  In essence, it’s just like the power brakes on your car.  If the power brake pump stop working, you still have brakes, but you just have to push down a little harder.

According to Denis and those who have driven the prototype, the hydraulic down-pedal can’t help but make a flatty pilot drive better, with more consistent and faster ETs and hopefully higher top speeds  You can’t ask for much more than that.

While in the midst of developing the product, Denis formed a friendship and later a business relationship with Paul Barber of Ottawa, Canada on the forum.  Paul is nearly a clone of Denis, a flatbottom aficionado to the extreme and a mad-scientist type of ace machinist.  The two have now partnered in a new company appropriately called the Billet Brothers where Paul will be responsible for manufacturing the units and Denis will stick with R&D and be available on an as needed basis for installations.

“I’m really excited about the potential of this product,” says Paul.  “I’m almost done with my full restoration of a 1975 Hondo like Denis’ and it will definitely have one of these units.  I don’t, however, want to give the impression that the hydraulic down-pedal is an off-the-shelf kind of product, because it isn’t.  There’s still some custom fabrication that needs to be done since virtually every V-drive boat is set-up a little differently.  I just need to know a few critical measurements when the order is placed and we’re good to go.  If done correctly, the installation of the unit takes a day or less and shouldn’t even require drilling any new holes in the stringers or mounts.

Currently, the retail price point for this unique product is $3,500 for the complete kit.  Compared to what props and other custom billet marine hardware are going for these days, it doesn’t sound too bad, especially when you consider what you’re gaining in the way of driveability and control.

“Without this hydraulic down-pedal, I think my flatbottom driving days would probably be over,” says Denis.  “That wouldn’t make me happy.  Now I just have to worry about not having any more of my body parts go bad and I should be enjoying myself and my boats a whole lot more.”

Editor’s Note:  approximately a year after this story was written, Denis reportedly struck a sandbar  while driving his Hondo flatty on Lake San Antonio at a high rate of speed and was fatally injured.  Our condolences to his family, many friends and members of the V-Drive Outlaws.



Updated: December 6, 2012 at 12:47 am