Sterndrive for fast amphibious vehicle

Discussion in 'Sterndrives' started by Bert Amphibious, Mar 1, 2018.

  1. tom kane
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    Location: Hamilton.New Zealand.

    tom kane Senior Member

    So many ways to make a really robust Steerable, Retractable drive that can take any power.
     
  2. myark
    Joined: Oct 2012
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    myark Senior Member

    Hi Bert
    This ww11 amphibian reminds me of your design

    It's possible this is an Aqua Cheetah.
     
  3. Bert Amphibious
    Joined: Feb 2018
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    Location: Belle Chasse Louisianna

    Bert Amphibious Bert Amphibious

    Big Difference is that my design did right at 45 mph in the water. I am working on modifications. The new skin is going to look very different than the one in the video. The new mod has Chevy Silverado lights. Silverado Windshield and new fenders. Also new mod will be running a prop with one of my own custom single joint Surface drives.
     

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  4. robint7777
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    robint7777 Junior Member

    Hey Tom

    I am looking for any information you can share relating to your pivotal drive. The attached pictures are of my present boat. It runs great with single or dual 225 optimax but I am planning on putting a diesel on it with a surface drive. However this is a diy project and I have no experience with surface drives. I would love to understand where best to install whether it is at the transom or perhaps a bit farther outboard where the engines are presently hanging. The second issue is the hull design, It draws an immense amount of air under the hull and I am not sure if I should stay farther back to try for cleaner water or ??

    I would enjoy hearing from you. Robin
     

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  5. gonzo
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    gonzo Senior Member

    Hi Bert:
    Have you considered a jet drive?
     
  6. tom kane
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    tom kane Senior Member

    Seems to me you should be looking at the work done by the "original" surface drive of Hickman`s Sea Sled racer, you should be able to Google lots of info. And on this website. My drive is really a conventional shaft drive as installed in lots of boats but the difference is that I made it so the shaft is able to be lifted up and down and steer from side to side at the helm, using the same standard parts. and it can be installed in many positions. It can take all the power that a conventional shaft drive can take. I will keep in touch with this thread and possibly supply more information as requested.
     
  7. robint7777
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    robint7777 Junior Member

    Thanks Tom, Specifically I would like to clarify the physical arrangements, ie slot, or thrust bearing location and style, u joint style, type of boot

    Any help would be great Robin
     
  8. Bert Amphibious
    Joined: Feb 2018
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    Location: Belle Chasse Louisianna

    Bert Amphibious Bert Amphibious

    The amphibious car you see in the video is running a Berkeley 12JCA JET DRIVE pump. It did a little better than 45 mph in the water; it also can smoke the tires on land. It was FAST just not fast enough to get anybody to notice. I had the Coast Guard guys and the Wildlife & Fishy guys looking at it several times. The design is a "Prototype" I was trying to target a design that could be used by government agencies and utility companies for FLOOD RESPONSE vehicles. One of the Wildlife & Fisheries head managers liked the concept but polity said "NO F***ing Jet Pump. After hurricane Katrina marsh grass clogged up all the jet pumps they had. He also said that the Prototype Design was TOO small. They want something a little bigger than the big box style ambulances (8'wide x 27'). They want to be able to stand-up and walk around in it and haul 10 to 12 people. I am working on a 8' wide x 27' long design for Flood Response service with more ground clearance bigger tires 4x4 FAST with a huge surface drive. That is what they want I am pretty sure I can make it happen. I just have to sell my 50' Coastal Cruiser to finance it.

    In the meantime I am currently modifying the existing Amphibious Car and outfitting it with a "single joint" Surface Drive of my own design. I am hoping to make a run at the Guinness World speed record late this summer with it; maybe that will be enough of a statement to get a little credibility. FYI if you look through a few of my post you will see a 5.5' long mini-boat with 7.5 hp lawn mower engine running the same type surface drive with a big 225 pound guy in it doing about 30 mph in the water. The tiny little single joint surface drive worked much better than expected. I am making a bigger version for the amphibious car.

    The idea is to be able to offer various amphibious Hull/Chassis kits with various choices of marine drives. Currently looking for people that may be interested in collaborating. We have numerous Aluminum Boat Fabrication Shops in the New Orleans area and many Auto Shops too. The concept is divide the project so that a couple of shops are supplying all the components and have one assembly location. Easier to control intellectual property that way; nobody gets a complete set of plans.
     
  9. robint7777
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    robint7777 Junior Member


    Maybe we should do a joint effort, modify my 30' seasled hull. Just add wheels and a surface drive. WP_20180513_19_39_21_Pro.jpg WP_20180513_19_39_52_Pro.jpg WP_20180513_19_39_52_Pro.jpg
     
  10. robint7777
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    Location: BC, Canada

    robint7777 Junior Member

  11. tom kane
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    tom kane Senior Member

    Diagram for Retractable Shaft drive, motor installed conventional inboard. Anything you can do/set up with conventional shaft drive you can do with a Pivotal Retractable drive, and more. Such as shaft through the transom. Image is parts for shaft through transom. Stainless Steel flexible seals and rubber/neoprene covers/seals are available. You would need to search for suitable ones for your own personal drive. There are retractable drives using C/V joints but they are more difficult to install, because of where they have to be installed. There are Wide Angle Cardan C/V shaft available for greater steering and retractable angles. U_V set up altered.jpg Assembly steerable drive.png

    U_V set up altered.jpg
     
  12. Bert Amphibious
    Joined: Feb 2018
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    Location: Belle Chasse Louisianna

    Bert Amphibious Bert Amphibious

    I would consider collaboration but I am in South Louisiana and your in Canada. Kind of tough with that distance. Are you really serious about making a 30' Sea Sled Amphibious??? What are your goals and or expectations?? Speed on land, speed on water, ground clearance? Kind of tough to design without a design criteria. What is the width and the weight of the hull? Making it a fast amphibious truck is tougher tan you may think. Just search on the internet there are a few slow amphibious kits but very few fast amphibious cars out there. Not too sure what the laws in Canada are; do you want to make it street legal? We have width limits here in the most states in the USA have a 8' wide rural street limit without permit and Federal highways have a 8'-6" wide limit.

    There is some really trick stuff to getting the tires to pull up high enough and wheel well design to limit the drag. I think if you limit your design to an off-road type design and hang retractable wheels off the side to makes the design a lot easier but that may not meet your expectations of ground travel. Also I think a surface drive of some type whether it is a pivotal drive or an Arneson drive or even an old Mercury Six.

    Personally I like big inboard engines for something like this 500 plus Horsepower and spin a ASD#6 prop or similar. I am a little curious what self aligning thrust bearing Tom would recommend for that application with a Pivotal Drive. I have been making my temporary prototype shafts using 1.375" diameter ETD 150 material (150 ksi stuff but still machinable). ETD 150 alloy is basically a modified 4100H alloy steel, processed to obtain an as shipped tensile strength of 150 ksi. I machine the shaft splines with a Bridgeport Mill and Cincinnati Indexer. Minimum U-Joint Spicer 1350 for the application. For amphibious application look at the SCS
    Transfer Cases. I had them make me a custom unit before. They are made for Monster Trucks 1.75" output shafts and 1410 U-Joints.
     
    Last edited: May 16, 2018
  13. robint7777
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    robint7777 Junior Member


    I forget where I have a reference to the US military doing studies on a sea sled hull, but if I remember correctly they came to the conclusion that it was about 85% as efficient as surface piercing hydrofoils.

    Bottom line is my own experience is this is a very heavily built boat. 7000 lbs. Even with that weight a single 225 optimax moves it nicely up to 38knts or so. Twin optimaxs pushed it to 46 easily with more potential by re pitching the props.

    I am thinking about s300 hp or so diesel with a surface prop would be a good result.

    Yes, the distance is not ideal, worse because I am in West Coast.

    Not sure where you are at on your design parameters but a sea sled hull is an interesting consideration because of the air lubrication of the hull.

    Very nice car/boat so far though.

    Robin
     

  14. Bert Amphibious
    Joined: Feb 2018
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    Location: Belle Chasse Louisianna

    Bert Amphibious Bert Amphibious

    Yes Robin I agree that a 300 hp Diesel turning a surface drive should work just fine for this hull.
    If you were going to make it amphibious I would go for more horsepower due to the extra weight and some additional hull drag associated with wheel wells.
     
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