Small diesels in sport fisher?

Discussion in 'Powerboats' started by Seafarer24, Jul 7, 2012.

  1. Seafarer24
    Joined: May 2005
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    Seafarer24 Sunset Chaser

    My 35' sailboat sank and I am having the Perkins 4.108 (50HP) pulled and pickled. I've found a Pequod 34 with no motors for what seems like a reasonable price. I was thinking of getting another 4.108 and putting the pair of them into this boat to make it into something like a trawler.

    I'd be perfectly happy to get 10 knots out of it- do you think this is possible?
     
  2. TeddyDiver
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    TeddyDiver Gollywobbler

    Might do ok except think you need to recalc the drive train and get new gearboxes etc..
     
  3. keysdisease
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    keysdisease Senior Member

    A friend something similar with a 40' sportfish and he's quite happy with it. I don't think you'll see 10 knots from a combined 100 HP though, I think you would do better to sell the perk and do a single of 200+. The perk with the added cost of the second engine + 2 x struts/shafts/props/drag may even cost more than just buying a 6BT from a Dodge pickup and marinizing it.

    Steve

    Steve
     
  4. mydauphin
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    mydauphin Senior Member

    The boat is design for two engines, but installing two small engines is same work as install two regular engines. Then you have gas to diesel conversion also. Might need new props too. I would go with like 200hp diesels for all the trouble and might better match present props. Start with your present props and tranny and then see which engine will give you say 14 knots at full throttle and work back from there.
     
  5. Seafarer24
    Joined: May 2005
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    Seafarer24 Sunset Chaser

    I don't want to give the impression I can afford one 200HP engine, let alone two.

    If I just installed the single Perkins, would the boat be manageable in reasonably calm weather? I really just need to move it short distances as it will mostly be at anchor while I live aboard. Then I could install a second engine later, maybe a 4BT Cummins as I know someone who can get these pretty cheaply and marinize them. Eventually I could replace the Perkins with another 4BT.

    I can't imagine needing a pair of 6BTs, and I certainly wouldn't want to / couldn't afford to feed them.

    What would you expect maximum displacement hull speed to be?
    Minimum planning speed?
     
  6. MechaNik
    Joined: Jan 2011
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    MechaNik Senior Member

    Certainly there must be something better available than a Pequad 34 as a live aboard. You are sacrificing much to have planning type hull and you do displacement speeds only.
    Not trying to put you down but it seems like a poor investment if it doesn't have the right engines to do what it was designed for.
     
  7. keysdisease
    Joined: Mar 2006
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    keysdisease Senior Member

    If I just installed the single Perkins, would the boat be manageable in reasonably calm weather?

    If you installed it off center as in directly replacing one of the old motors than you may only go in circles. Small Sportfishers with hi speed rudders often don't do well on one engine.

    If you sell the perk and buy a 4BT from your friend and mount it centerline, now you have something that will travel.

    You could probably use the old shaft, packing gland if rubber hose type, maybe strut, maybe the prop by reducing the diameter. You would have to glass in a fiberglass tube for the shaft and of course plug the existing shaft holes. You could leave the rudders, they would be effective underway but less in maneuvering from lack of prop wash.

    Just thinking out loud

    Steve



     
  8. Seafarer24
    Joined: May 2005
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    Seafarer24 Sunset Chaser

    It's a beautiful boat for only $3,000. It has plenty space for me to live in, as my parents will let me use my old room at their house for storage. My anchorage has public bathrooms and showers, also.

    I'll scrap the idea of moving it with only one engine. Certainly not going through the hassle of converting to a single center-mounted engine.
     
  9. whitepointer23

    whitepointer23 Previous Member

    bolt a pod on the transom and put an old 70 hp outboard on it. that will push you around at 6 or 7 knots when you need to move. later on when you can afford it put twin diesels in. just leave the shafts and rudders in place.
     
  10. keysdisease
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    keysdisease Senior Member

    Or just get someone to tow you when you need to move. I towed my Mainship 34 with a 10ft dink and a 6HP outboard over 2 miles once, it was calm and we made very impressive speed, like 3-4 knts.
     
  11. Seafarer24
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    Seafarer24 Sunset Chaser

    Haha, I once strapped my 7' dinghy with a 2.5HP outboard to the rear quarter of my Cal 35 and pushed it that way.

    I do have a Yamaha 4-stroke 9.9HP High-Thrust Long-shaft that I could mount on the swim platform.... It's a tiller motor though so I would need to have one person operate the motor while the other stood on the bridge and shouted directions...

    ...that sounds safe.
     
  12. keysdisease
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    keysdisease Senior Member

    That 9.9 will push that boat just fine, I'll bet yo might hit 5 knots. The rudders will probably respond once underway.
     

  13. Seafarer24
    Joined: May 2005
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    Seafarer24 Sunset Chaser

    The motor itself can be turned so rudder response isn't as critical.
     
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