Surface Drive For a fast Amphibious Vehicle

Discussion in 'Boat Design' started by Bert Amphibious, Feb 18, 2018.

  1. dinoa
    Joined: Oct 2007
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    Location: florida

    dinoa Senior Member

    Nice piece of work.
  2. Bert Amphibious
    Joined: Feb 2018
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    Location: Belle Chasse Louisianna

    Bert Amphibious Bert Amphibious

    Thanks I need to start a few new threads in different categories. Yep I have been looking at the Russian amphibious stuff. I haven't seen anything that Russian's have that is fast on both water and land yet. The Sherp is pretty cool.

    I was in the O&G business for about 40 years I got to be a little creative in that field but I really wanted to do some of this marine stuff. I was too busy running O&G projects to do it until now. I didn't have the time to build and try the things floating around in my brain for over 40 years that I never acted on. Example this is surface drive design I almost patented in 1979 I came up with in 1973 as high school working as a mechanics helper in my dads gas station garage. I may still get around to patenting some aspects of it.
    The design advantages are:
    · Very cheap and easy to build. All plate and tube construction. No castings are required. Only a lathe and a welding machine is needed to fabricate item.
    · Hull is well sealed from water leaks. Water has to leak through the bellows and through two grease seals to get into the boat.
    · The bellows seal can be air tested for seals on dry land before going into the water. Multiple bilge and water leak detection systems can be used on in the bellows area. The bellows can even be changed underwater if needed and special installation techniques are used.
    · Can run as a fully submerged prop or as a surface drive depends on application.

    I am not out selling plans or kits for the single joint drive yet but Jake can sell you a modified version of one with his Mini Boat we have a hand shake on it. Boat in video is only 5.5 feet long and uses a 7.5 Hp motor from Harbor Freight with a tiny single joint surface drive guy in video is over 220 pounds and it ran about 30 mph. I should post it separately for him in a different category see

    I am in the process of building a big one to test on an Amphibious Car design.
    IMG_23271.jpg MiniBoat Video Jake.gif
  3. myark
    Joined: Oct 2012
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    Location: Thailand

    myark Senior Member

    Roycroft plaining BIG.jpg ROYCROFTS AMPHIB BIG.jpg
    Hi Bert
    Great to see ingenuity on boat design
    View attachment 138689 View attachment 138690 View attachment 138689 View attachment 138690 View attachment 138689 View attachment 138690

    Hi Bert
    Well done
    I have attached a friend Terry Roycrofts amphibious idea in the early days before Gibbs Aquada - Gibbs Amphibians arrived at his place by helicopter and purchased the design from Terry, Your design has great potential because of the speed and low cost.
    Well done
  4. OCB
    Joined: Dec 2015
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    OCB Junior Member

    Very nice project! I like your idea of designing it as part as the everyday service fleet. The LS with TH 400 and 205 gear case is boom proof. You can spit the power from the LS-7 you can run two surface drive at the speed. In low range you can spin a big prop slow.

    I also like the design the idea of your single joint drive? What kind of joint do you use?

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

    Bert Amphibious Bert Amphibious

    Yep *OCB* I like the NP205 Transfer Cases easy to modify so that output shafts operate independently. I also like that you can get them in a divorced case style and do the same that way a short input drive shaft is used and just about any engine/transmission can be connected to the input. Also I designed and made my own Adapter so that I can take a standard NP205 that is mounted to a transmission and turn it into a divorced case. The machining isn't to hard just a few hours on the old Bridgeport Mill using the boring head.

    I built a small prototype single joint surface drive with a Spicer 5-170x U-joint and partially built a bigger one with a 1350 U-Joint. I am looking at trying to get a 1410 U-Joint into a Mercruiser #6 U-Joint Bellows.

    FYI I also went one step way beyond past that I built my own custom gearbox divorced style Transfer case using NP205 gears. Added a few more output shafts. It weighs just a touch more than a regular NP205. It is also a two speed case but on one side it has an input 1350 U-joint Yoke and two 1350 U-Joint output yokes. On the other side of the case it has three outputs (shafts are common shafts run through the box) The shafts can be run High neutral or Low). I can run 4 wheel drive, marine drive and a PTO for whatever. It is shown below without the 8 pattern Bolts.

  6. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    interesting, IIRC the jetski VS snowmoblie contest physics was about the greater AREA of the tread VS the pump inlet.

    Got a number of the Navy patent? I'm pretty sure similar stuff was at least thought about long ago, so a general patent would be worthless.
  7. OCB
    Joined: Dec 2015
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    Location: USA

    OCB Junior Member

    Some time ago I have work with the 205 on 4x4 trucks with big tires. We got a kit to add a 208 transfer case to get lower then the 1.96 stock low range. Now I use the atlas transfer case is much lighter then the cast iron stock one. Lots of gear ratios.
    Atlas Transfer Cases | Chevy Transfer Cases | Advance Adapters

    I am working on almost the same idea of a short surface drive. I started with bravo gimbal housing to use the steering and trim for less manufacturing cost. I designed a new type universal coupling to stay away from the U joint the is to small in the bravo drive design.

    I have been working on more outputs for my transfer case as well. How many outputs in your T case have. I have a old Vemco case from the 1970's with 2 froward 1 to the rear.
    vemco 4x4 - Google Search

    Last edited: Feb 27, 2018
  8. kach22i
    Joined: Feb 2005
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    Location: Michigan

    kach22i Architect

    I think his Facebook account is still active, that's how I heard he had passed, the news hit me in the nads even though he was just a forum and e-mail buddy. Someone was talking about cool uncle David with all of his great inventions, and similar to you my first thought was like yea- what's going to happen to all that cool stuff now? I'm assuming it went to auction or some of the relatives have some of it. He knew he wasn't in good health for a while, hopefully he planned his legacy well as was not in denial. Try poking around Facebook maybe you can turn something up.

    When my aunt was sick she said she was going to beat it and didn't make a plan-B (a will) for her son and her assets. I think the state got more that he did.

    Your design has a couple of really strong points lacking in similar attempts, it has size and it sits low enough for over the side rescue operations.

    Keep up the good work.
  9. Bert Amphibious
    Joined: Feb 2018
    Posts: 23
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    Location: Belle Chasse Louisianna

    Bert Amphibious Bert Amphibious

    Thanks for the reply. Lets's share info if we find out anything more.

  10. Nikola Webster
    Joined: Mar 2021
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    Location: USa

    Nikola Webster New Member

    Hi there,
    Not sure if you know this or not, but you can ride the original amphibious cars. The ones that Hans Trippel, a German designer, created. The Amphicar Model 770 debuted in 1961. The vehicles were produced in Germany by Quandt Group and available to buy from 1961 to 1968. Production stopped in 1965 with 3,878 produced, of which 3,046 were imported into the U.S.
    The only place in the world where you can ride them (unless you own one) is at Disney Springs in Florida: Amphicar Disney Springs - The Most Unusual Attraction •
    Also, Mount Dora in Florida has an amphicar festival every year where many owners come and display their cars on the water.
    You should check it out if you are into amphibious cars; the history alone is fantastic. Riding one - WOW! Enjoy - Nikki
    BlueBell likes this.
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