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Converting to a single diesel engine.

Discussion in 'Hatteras Yacht' started by Dcal1968, Oct 19, 2017.

  1. Dcal1968

    Dcal1968 New Member

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    I'm new to the forum and I've been given a 1964 Hatteras 34ft double cabin, it will be a live aboard project. Has any one ever converted one of these to a single engine?
  2. chesapeake46

    chesapeake46 Senior Member

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    The yard I am at took an F-32, added 8 feet, removed the gassers and installed a single CAT.
    Then the owner's girlfriend decided she wanted more state rooms & such so the boat is currently for sale.
  3. Ormond Bert54

    Ormond Bert54 Senior Member

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    Imagine the amount of money that person wasted. Then try not to do that. Generally, changing to different power to or one instead of two is an enormous expense that will not be recovered.
  4. Lepke

    Lepke Member

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    Any major modification or engine change is only worth the price if you plan on running and keeping that boat for many years. Twins to a single mean new engine beds, properly tied into the hull to take the weight and thrust. It would be better to stay with twins. It would probably be cheaper to rebuild the twins than remake the engine room, even if someone gave you the new engine.
  5. ranger58sb

    ranger58sb Senior member

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    What is the current power? What would be your goal with the conversion?

    Not the same, but an anecdote: Boat neighbor had an '80s 35 gas Bertram in good condition worth (my guess) about $50K. Blew an engine. Repowered with diesels, and swapped out gas genset for diesel, too. Cost about $100K. Afterwards, the boat was worth about $60K.

    Might get similar results from the conversion you propose...

    -Chris
  6. Dcal1968

    Dcal1968 New Member

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    It has 2 Crysler 440 gas hogs that are no good, but I have a rebuilt DD 4-53, 185 hp. I want to convert to a single diesel for long range cruising. Otherwise I'll find another DD 4-53. I just prefer the 4-53, it's very economical and reliable. It will be a live aboard and I don't plan on reselling it. I want to convert it to a single screw to make it as economical as possible for the long range cruise. Even with twin 4-53's it would still a fuel sipper. Thanks for the reply.
  7. Capt Ralph

    Capt Ralph Senior Member

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    Your draft will near double.
  8. Dcal1968

    Dcal1968 New Member

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    That's why I'm wanting to convert to a single engine. However, twin DD 4-53's was an option on that year, i think ill reach out to Hatteras and see what they recommend. Thanks for the feedback.
  9. Capt Ralph

    Capt Ralph Senior Member

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    I did not mean hull draft, I meant running gear; Prop & rudder will be much lower in the water.
    When was the last time you operated a single V hull around a dock? Bring lots of spring lines and fenders.
  10. olderboater

    olderboater Senior Member

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    Take the least difficult and least expensive option. Get prices on all options. The right solution could well be dropping in gas engine replacements. It takes a lot of cruising to eat up the savings in engine price. I don't know the right solution. I seriously doubt it's going to a single. I don't know how much more twin diesels vs twin gas with everything else that goes along with the job.

    Talk to Hatteras/Sam's on the issue. They'll have diagrams of the boat, engines that were offered, and what would be involved. They likely will be able to go right to your boat if you give them the HIN.
  11. Dcal1968

    Dcal1968 New Member

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    I have a 27ft single v-hull in my slip right now, but you probably mean something a bit bigger...I guess.
  12. Capt Ralph

    Capt Ralph Senior Member

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    IB, OB or I/O; I'm sure it was designed that way.
    Your changing the power install that the original boat was built for.
  13. Dcal1968

    Dcal1968 New Member

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    Why do you doubt that the solution is going to a single. I have a rebuilt diesel already, seems like a reasonable solution. I'm not trying to be curt, I'm genuinely intersted in why you think that it's not a viable solution.
  14. Dcal1968

    Dcal1968 New Member

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    IB
  15. Capt Ralph

    Capt Ralph Senior Member

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    Has any one ever converted one of these to a single engine?

    Answer;
    No, Nobody here has converted one of these to a single engine.

    There are engineers, designers, mechanics, fabricators and rednecks from all over the world here at YF. Amazing nobody has converted one of these to a single engine.

    I'm sure the same results will be found at other sites.

    But somehow the responses and answers still escape you.
    Last edited: Oct 23, 2017
  16. olderboater

    olderboater Senior Member

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    As Ralph just said, you're not listening or reading between the lines. A single presents many problems to install and extensive costs. You can ask Hatteras if they ever built any of those with singles. But you have to get and install an entire drive train, remove and patch two engines, Add support for an engine in the middle, cut a hole in your hull for the new drive train, figure out some way if you wish to protect it and the prop since it will be much deeper draft than before.

    Besides, you'll have to pay someone to do all this if you want it done right as it's obvious you don't know how to do it.

    Right now you have a boat that is worth about $0
    You have an investment of $0

    Go through all this and you'll have a boat worth $10,000
    and you'll have an investment of $60,000.

    I suggested already you call Hatteras/Sam's and see if they replaced any gas with diesel. Stick to two engines. If you discourage the diesel exchange, just replace the two gas engines with gas engines.
    Last edited: Oct 23, 2017
  17. ranger58sb

    ranger58sb Senior member

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    I'd expect, in order of expense, that replacing twin gas with twin gas, or replacing twin gas with twin 4-53s, could be easiest/fastest and maybe even least expensive in the long run -- given additional engineering changes associated with changing to a single.

    Depending on how much mileage you plan, gas fuel usage can be much cheaper than replacing engines with diesel and then hoping to amortize that cost over your lifetime. Replacing old 440s with new Crusaders (or whatever) with new technology... could make periodic fuel consumption less painful anyway.

    If you expect to put boatloads of miles on the thing, I'd probably lean toward twin 4-53s, myself (of your options). BOATLOADS of miles. OTOH, fuel -- for many folks -- is often not the largest cruising expense anyway.

    Genset onboard? If so, you'd want to change that to diesel too, if you go with a 4-53 option.

    -Chris
  18. captholli

    captholli Senior Member

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    Dcal1968, Its a great idea you have to convert this vessel's machinery but unfortunately this boat is a bad platform for your intended use as a long range cruiser with a maximum 200 gallon fuel capacity. Even at a snails pace of 5 knots sipping fuel with your rebuilt 4-53 you'd not have that much range. Sell the 4-53 to offset the expense of repowering with new gas engines and enjoy your boat as their are no financially viable options for this conversion.
  19. bernd1972

    bernd1972 Senior Member

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    I don´t see a benefit in going down to one engine. The fuel consumption is determined by the an amount of horsepowers for the desired speed. A twin engine configuration is about 15% less efficient compared to a single engine with lower rpm at the shaft and bigger prop If you stay with the gearbox and prop size you currently use the single engine will be pretty ****** even compared to a twin engine configuration. Furthermore you need to compensate the weight you remove which will be about 600-700kg to avoid messing up the stability. So even no weight reduction.
    In total, considering all aspects, i can´t see what should be attractive about wasting a small fortune on castrating your boat. Converting to diesel is a different thing - if you can get adequate engines at a reasonable price and the engines installed are scrap anyway I´d support that idea.
  20. Capt J

    Capt J Senior Member

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    The most economical way would be to put 2 4-53's in it and utilize all of the existing stuff.....shafts, struts, (just reprop), exhaust holes etc. You have A LOT of stuff to glass in and change to convert to a single..........A long range cruiser, well it depends on what you consider a long range. Even with 200 gallons of fuel, with 4-53's, if you did say 6.5-7 knots (hull speed) you should get 1.5 nmpg with 4-53's......maybe even 2 nmpg......And, you'll never recoup the money you throw into it.......