Question ; Single Inboard Conversion To Twin

Discussion in 'Powerboats' started by RYANPO, Feb 13, 2006.

  1. RYANPO
    Joined: Feb 2006
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    RYANPO Junior Member

    I have a 28ft Lang Sportfish with a 11' 6" beam. It has a long and deep keel and plains out in the stern. It is currently powered by a chrysler 440 which sits in the dead center of the boat between the stringers. The prop shaft exits out of the rear of the keel. I am trying to figure out if there is a way to have twin engines. The engine bay could possibly fit two small blocks infront of another but probably not side by side due to the narrow hull. However I am unsure if that is possible with the shafts? The stern of the boat has only about 17" of clearance from the end of the keel back to the remaining 8 or so feet of the stern. The other idea was if it was possible to stagger two small blocks in the engine bay area. I would love to convert to diesel. Is there a such thing as twin 4cyl diesels, pushing an 8500 lb deep V about 15 + knots? Any info would be appreciated. thanks
     

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  2. Corpus Skipper
    Joined: Oct 2003
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    Corpus Skipper Hopeless Boataholic

    My 26' Chris Craft, 10' beam, has twin Crusader 350s side by side, with plenty of room to spare, and even has saddle tanks outboard of them.
    HUH?:confused: Maybe this picture will help.
    Sure, twin Cummins 4BTAs will push an 11,000 lb Bertram 28 to 19 or 20 knots, and cruise at 17-18 kt. But if I were you, I'd keep the single screw, and put in a 6B Cummins or Cat equivalent. Much simpler, cheaper, easier to maintain, more fuel efficient, leaves room for a genset, a/c, all the other goodies, less weight, shall I go on? MANY long range offshore vessels are single screw. New engine with good maintenance will be very reliable.
     

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  3. longliner45
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    longliner45 Senior Member

    how much money do you want to spend?
     
  4. RYANPO
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    RYANPO Junior Member

    i keep my boat in Brigantine NJ. Unfortuately I am about 30 years from retirement but enjoy fishing spontaneously offshore and want something reliable. Most of my trips will be within 40 miles offshore but I would take trips after work and hopefully return by morning. So I dont have the time to wait for the Tow Boat to come pick me up. Besides I just want one less thing to worry about. I've been on single engine diesels 80 miles offshore, but i guess its the security i want, even if its rebuilt twin 4cyl diesels.
     
  5. longliner45
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    longliner45 Senior Member

    How about volvo diesle ? 4cly very reliable. you could put1 in and then a small emergancy engine that is belt drivin off the shaft
     
  6. RYANPO
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    RYANPO Junior Member

    volvo diesel would be fine, i was just more familiar with cats, yanmar and cummins. If i was going to stick with one main engine i would probably have to go with a 6 cylinder diesel. How hard of an application would a small belt driven application be to install.? thanks for the info
     
  7. longliner45
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    longliner45 Senior Member

    Id go with the 6 also just thought you wanted some economy but the 6 will go good cat ,yanmar or volvo. a good onan or 2cyl diesle a pully with slack adjuster,,,,a lever to pull ,would work in place of 2nd engine.
     
  8. fisherboat
    Joined: Feb 2006
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    Location: USA

    fisherboat New Member

    Would You Like To conversion with hydrofoilic?

    Would You Like To single inboard conversion to hysucat hydrofoil technology.
    The HYSUCAT® system was adopted by Malan Conradie, and he started building semi-rigid inflatables in conjunction with Prof Hoppe. The hull design was altered and improved until Malan felt that he had got the best shape and performance available — and this hull-design is the one that has now been implemented throughout the range of STEALTH yachts.
     
  9. johny74
    Joined: Nov 2006
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    Location: Howard Beach,NY

    johny74 Junior Member

    Lang Power

    Hi,
    I also have a 28' Lang! Its recently repowered with a 5.7 Marine Power carb. The engine is rated for 315hp. On cruise at 3k I average around 13-15 knts depending one the seas. WOT at 3500 I hit close to 18-20 knts on the gps. Forget even thinking about putting twins in that boat. First she wasn't built for it, two why waste all that money in trying? The boat is not made to plane out. Two options you can do for power, one is upgrade the gas engine to a 502 merc, crusader, or even marine power. You will be more than happy with that power option. Second you can always repower it with a yanmar diesel. But with diesel you will never get the power your looking for unless you go big and you have plenty of room in the engine compartment to do it, but I personally think it would be a waste. Honestly the BEST thing you can do for your Lang is install splash rails. You will get more speed, better fuel economy, and can be done for under $500.00. Twin engines has it pros and cons. Pros are docking "on a windy day lol" and reliability. Cons, ready? More fuel consumption, double the headaches when they break down and maintance. I'm gonna start redoing the outside over. Would love to see more pics of the boat. You can email me at johny74@aol.com. I'll send you pics of the new engine installed. We'll swap pics!
    John
     
  10. Verytricky
    Joined: Oct 2005
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    Verytricky Large Member

    I think you mean very wide hull! you can probably fit 3 small block engines in an 11.6 space!! Definately 2 with no problems. Definately 2 oil burners.
     

  11. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    Ryanpo, Study the economics of the situation carefully before dumping a bundle on this boat. The cost of converting to twin or even a single diesel will not balance out the option of simply repowering with more hp gas. You would have to run the boat a lot for the fuel cost differential to make up the difference. If you have the resources and knoledge to do this project yourself, then I would shop for a suitable project boat that is capable of the speeds you need. BTW, your cinder block stacks make me nervous! Don
     
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