diy surface drive.

Discussion in 'Surface Drives' started by mike08kurtz, Dec 22, 2014.

  1. mike08kurtz
    Joined: Dec 2014
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    Location: phoenix AZ

    mike08kurtz New Member

    hello, i know this has been talked about before but im looking to do it a little differently i believe. a 700r4 automatic transmission from a car 3rd gear is 1:1 ratio. overdrive .70:1..... I think running a transmission out the rear of the boat to a yolk slip with a surface piercing propeller would do the trick! using a rudder system to steer and trim tabs for trimming the boat. i got my inspiration from this picture off of an old 70's surface drive! [​IMG]


    Running it out just a tad further then this one!



    To handle the thrust, i am thinking of using a block bearing mounted on the cone of the transmission like this much more heavy duty of course.

    [​IMG]




    and just for a refference when i say 700r4 this is it!! [​IMG]
     
  2. CDK
    Joined: Aug 2007
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    CDK retired engineer

    Nice! Is there any evidence the boat in the picture performed well? The prop doesn't look like a surface piercer.

    More inspiration: www.q-spd.com
     
  3. mike08kurtz
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    mike08kurtz New Member

    well i know that this boat came with it. how it performed im not sure. it looks a little short to be as effective as today's drives. Arena Craft made these surface drives runabouts in the 70's any input is appreciated! thanks for the reply.also if you can see any holes or improvements don't hesitate! i take constructive criticism very well
     
  4. mike08kurtz
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    mike08kurtz New Member

    i believe this is the boat with that drive

    [​IMG]
     
  5. Brent AZ
    Joined: Aug 2010
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    Brent AZ Junior Member

    I too have been doing research and gathering information in preparation for the rebuilding of an older boat and to change it to a surface drive setup.

    Mike, I live in Phoenix also and your idea of using a 2-speed transmission along with a surface drive is the same idea that I have.

    My boat is a 1976 Hallett 23ft day cruiser. It came from the factory with a 454BBC engine with a Mercury TRS outdrive and a single speed Merc-Trans transmission to provide Forward-Neutral-Reverse. Hallett let its customers order this boat with either a jet drive, a V-drive, or the inboard/outboard setup. The only difference for the hull between these setups was the use of a metal cavitation plate mounted across the back of the transom for the jet and V-drive setups. Here is a photo of a boat with the same hull as mine.
    1978 HALLETT Day Cruiser-2.jpg 1978 HALLETT Day Cruiser-3.jpg

    I will be using this boat for many different functions such as: cruising the lakes, family boating, water skiing, and fishing. I will be upgrading the engine's power by increasing the bore & stroke to about 600 cubic inches producing around 700 horsepower and 600 lb/ft of torque. With this much power, the original TRS outdrive and transmission would probably not survive very well. The TRS drive is only rated to about 350 lb/ft of torque even though many users have subjected it to much higher power, but I wanted a drive setup that would survive abuse from anyone that asked to borrow my boat. I would hate if my boat came back to me after being borrowed and it had a broken drive unit.

    I first considered changing the outdrive to a Bravo I or Bravo III, but they are probably easier to break than the TRS unit. I then considered a V-drive setup because it can handle much more power than any outdrive that is within my budget. The outdrives that can handle the power level that I desire are much too costly for me to consider. I was able to purchase a new old-stock Arneson 1720 surface drive for a good price and I am considering using it. I also have a Casale V-drive unit.

    So I have narrowed my drive choices to using either a V-drive setup or a Surface drive setup, but I am actually considering a combination of the two setups. The engine would be placed as far to the rear as possible with a 2-speed transmission attached facing forward, then coupled to a Casale V-drive box to send the driveshaft to the rear and also allow the drive shaft's down angle to be set to about 2-4 degrees to travel beneath the engine and exit out the transom just above the bottom of the boat. The Casale will allow me to inexpensively change the gear ratio to fine tune the boat's performance at much lower cost than is possible by changing the transmission's ratio or the propeller. That way I can purchase less expensive surface drive props that come available from time to time instead of buying a custom expensive prop designed specifically for my boat's operating configuration.

    I also decided to use a 2-speed transmission because I wanted to be able to pull water skiers and then later go racing against my buddies boat without needing to change the prop for the two different situations. Also the low gear will help the boat get up on plane quicker as it will help to keep the engine in its upper rpm power band range as the boat gets underway. And it could even be kept in the low gear for general boating where the speed is not likely to exceed 40 knots, like when pulling the kids on water toys. I have an old-school B&M Art Carr transmission that was made from a Chrysler torqueflite 727 with 1st gear removed and a very short tail housing. This allows the transmission to be only about 18 inches long, much shorter than the TH400 GM transmission or the even longer 700r4, and the Chrysler 727 has many after-market parts to allow it to be upgraded to handle more than my power level since they were often used in supercharged drag strip automobile applications.

    I have to replace the rotted wood stringers and will replace the wood in the transom (I don't want there to be any wood left in the boat to rot in the future) at the time I fill-in the outdrive mounting hole. This will be a complete ground-up rebuild as there is not much left of the original boat except the hull that is worth keeping. The hull is a very high quality fiberglass construction. I will change the seating configuration by creating a driver's cockpit as far to the rear as possible just in front of the engine compartment and have a walk-thru windshield and then have a wrap-around couch front seating arrangement that will allow as many as 10-12 people to sit in the large front bow seating arrangement, like the photo attached, except that the center console in the photo would be replaced with a walk-thru windshield and positioned a little further to the rear allowing an additional 4ft more of seating to be placed on each side of the wrap-around arrangement. I can also fabricate a fiberglass foam core cover plate to attach over the top of the entire open area of the bow seating, gunwale to gunwale, to convert the boat to have a front walk-on deck like the bass fishing boats have.
    22ft Ultimate with Center Console open bow arrangement-1.jpg

    The engine would be placed just behind the driver's cockpit with the transmission under the full width driver's bench seat with the Casale drive placed under the floor at about where the walk-thru windshield passage is positioned. This will allow for easy access under the walkway floor.

    I was most concerned about a sharp propeller protruding far out the rear of the boat that could potentially injure people swimming up to the boat at the transom when a water skier would be picked-up out of the water or when the grandkids are diving off the rear of the boat into the water. The boat needs to be family friendly, even for those who might borrow my boat. I don't want to have any injuries from the prop or snag my fishing line on it either. So I have decided to add a large swim platform at the rear of the boat. There are many options for this platform design. The photos show two options.
    Large Swim Platform.jpg Extended Transom-2.jpg

    I am even thinking about building the transom extension to have a semi-circular water flow channel to direct and contain the water flowing from the bottom of the boat into the propeller in a laminar flow path like the shape of the water passage in a jet pump inlet that channels the water into the impeller.

    The boat will also have trim tabs that will allow me to better trim the boat's bow up so that I can get as much air under the boat as possible to reduce wetted surface water friction at high speed. These trim tabs will act like large cavitation plates used on the V-drive and jet pump configuration of this same boat. I am wondering if I should also build in a pad at the rear keel of the boat to aid the boat being lifted out of the water at high speed. The boat has a shallower dead rise angle compared to the typical V-bottom boat. Its bottom is very similar to the modern bass boats like the Allison.

    You can build your own 2-speed surface drive setup by simply converting a V-drive setup to exit the transom with the rudder extension. It would look very similar to the photos that you have previously posted. If you use a thrust bearing mounted to the transom, it will give your boat a similar thrust center of gravity position to other types of drive options. You could also opt to have a simple seal at the transom and allow the thrust to be applied to the Casale box which would put the thrust center of gravity well forward of the transom. The more forward thrust position will make your boat more straight-line stable and the rear thrust position will make the boat turn more easily.

    Send me a PM if you want to discuss what my plans are in more detail.
     
  6. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Why the choice of automatic transmission? In a car it works well because of the changing loads at the same speed. Also, because the wheels don't slip like a propeller does. It will have much higher power losses than a standard marine gear. By the way, a marine gear has all the thrust bearings already installed.
     
  7. whitepointer23

    whitepointer23 Previous Member

    I have owned and been in a few other boats with car automatic boxs and they work ok. Usually fitted with a tapered roller thrust bearing mounted on an angle steel beam behind the box. 2 spd powerglides use to be sold as a marine box with the torque converter and rear extension removed .
     
  8. WestVanHan
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    WestVanHan Not a Senior Member

    Sounds like a great project, Brent.

    I'm curious about the engine though. Have you considered a twin turbo LS, a junkyard truck 4.8/5.3 or 6.0?
     
  9. Brent AZ
    Joined: Aug 2010
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    Brent AZ Junior Member

    Gonzo - regarding the use of the automatic transmission - most times when an automobile automatic transmission is used in a boat, the torque converter is not used. A direct coupling or flex plate is used instead. This prevents slipping and loss of efficiency. This is exactly the way that Mercury Marine did it with their MercTrans that came stock in my boat. I've been told that the MercTrans is an adapted Ford automatic transmission. I do believe that the BorgWarner transmission (gear as it is called in boat language) used in most smaller boats is also shifted using the same principles as the automatic transmission used in automobiles. If the transmission needs automatic transmission fluid, then it shifts in the same way a car automatic transmission does, just not with all of the internal gearing.

    Most automobile transmissions that are adapted for use in boats have the shifting valve body replaced with one that changes it from automatic shifting to manual shifting so that it functions just like the newer ZF 2-speed gears.

    An automobile transmission can not be used for thrust loading because it does not have any thrust bearings built-in to it. In my layout the thrust will be taken by the surface drive unit at the transom or by the Casale gear box depending on which design surface drive unit I ultimately use.

    The only less than optimal design issue that I know about when using an automobile transmission is that the gear ratio is not very optimized for boating. The split between any two gears is normally .5 or higher and it should really be around .25-.3 for boats. The 2-speed GM PowerGlide transmission has this issue as does the 3-speed GM TH400 that are commonly used for boating. The Chrysler 727 that I am planning to use has a .48 ratio between its normally 2nd gear and 3rd (final) gear. Knowing this, it is important to setup the camshaft in the engine to have a much wider torque curve so that you don't loose too much torque when shifting. Depending upon the propeller used and how much of the prop is in or out of the water to accommodate slip allowing the engine to stay in its power range, just after shifting to the higher 2nd gear, can all help minimize the engine loading that can bog the engine upon the up-shift.

    WestVanHan - Regarding using an LS based GM engine- funny you should mention this. I have 2 all aluminum LS3 engines and I also have several turbochargers sitting in my garage. One engine is for another boat project I have and the other is for a Porsche 911 swap. You are correct that an LS engine that is turbocharged would be a possibility. It saves between 250-350 pounds of weight over the BBC and properly setup can produce 700-800HP. That is exactly why I have selected the LS3 to be used in my other boat project that is a 20ft Stoker SST. I plan to use the LS3 mated to a Mercury Blackhawk surface drive that I also have. The Stoker has a modified tunnel vee hull and was designed as a mod-VP race boat, so a Blackhawk surface drive will work well with it as the hull wants to ride on a cushion of air packed under the hull trapped in the tunnels. Naturally aspirated the LS3 can easily produce 450hp, which is about the limit of the gears used in the BlackHawk if I want to keep it reliable. Without turbos the LS3 could make the Stoker a 110+mph boat as they will go 90+mph with a Merc 2.5 outboard engine. If I wanted to go crazy and turbocharge the LS3, the Stoker could be a 140+mph boat, but I don't want to die like the other crazy fool that put a Nascar Chevy 350 race engine in a Stoker with a blackhawk drive and pushed it to 148mph. I was told that this man later died when he decided to go show-off and crashed his Stoker after drinking one day with his buddies.

    If anyone knows of a low cost set of water cooled exhaust manifolds that will fit the GM LS series engine, please let me know, as I will probably need a set for my Stoker project.

    I have selected the BBC for the Hallett rebuild because it is a very durable engine that can produce large amounts of power naturally aspirated. I wanted the Hallett to be as bullet-proof as possible because my kids & friends will be borrowing it and I want it to be easy to use with no bad habits and be hard to break. The BBC will have cast iron Merlin heads and a forged stroker crank and H-beam rods and forged pistons; 4.25 stroke X 4.60 bore. Engines setup like this can produce 700-800hp depending upon the cam and fuel delivery system. It is the torque that I am after and I will probably have a rev-limiter on the engine to prevent it from turning more than about 5500rpm even though it could probably easily go to 6500rpm. I have a really nice 52mm throttle body setup that can be used that sort of looks like a set of 4 twin throat weber carbs. Although it has been suggested to me to use a single 4bbl carb to keep it simple. Fuel injection, if installed correctly, can make for very easy starts and operation on the water, especially for those that borrow my boat. The previous owner of my Hallett told me that the 454BBC with the TRS outdrive gave him a top speed of 65-70mph depending upon boat weight and water conditions. I am expecting that with the changes I am making, the Hallett will have a top speed of about 80-90mph. That's more than fast enough to call it a "thrill ride".

    My next question is "How do I determine the Hallett's center of gravity so that I can determine its balance point"? The boat is on a trailer and I have the ability to lift it off either using one of two front-end loader tractors I own or with an overhead crane that can be rolled in place over the boat. I presume that I need a calibrated strain guage, or other means of determining the weight on the lifting chain, and then by lifting the boat at various points from bow to stern and running some calculations, I can determine its center of gravity in its current condition. Knowing the weights of the various drive and interior components, I can then add those weights to the calculations to determine the final balance point. So where do I lift from and how do I gather the weight measurements and what calculations are used? I figure that I need this information so that I can better determine the size and placement of the trim tabs. I know that the Hallett will need some help lifting the bow while running as the manufacturer would normally use cavitation plates to do this when this hull was setup for a jet drive or as a V-drive configuration.
     
  10. gonzo
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    gonzo Senior Member

    I you have a lift bar, the boat will hang horizontally when the attachment point is above the center of gravity; just like an equal arm beam scale.
     
  11. WestVanHan
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    WestVanHan Not a Senior Member

  12. TANSL
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    TANSL Senior Member

    I probably do not understand the underlined phrase but I think what you say is not correct.
     
  13. gonzo
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    gonzo Senior Member

    Do you know what an equal arm scale is?
     
  14. TANSL
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    TANSL Senior Member

    No, Gonzo, I donĀ“t know what is that. I will gladly read your explanation. Thanks.
     

  15. gonzo
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    gonzo Senior Member

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