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Repowering a 54' Donzi Sportfish

Discussion in 'Donzi/Roscioli Yacht' started by DOCKMASTER, Sep 5, 2019.

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  1. DOCKMASTER

    DOCKMASTER Senior Member

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    Christmas in February! Engines arrived CAT dealer. Gears are mounted up and being plumbed. Everything gets loaded on the truck and sent to barge terminal tomorrow. Should arrive Ketchikan early next week and then the fun really begins.


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  2. PacBlue

    PacBlue Senior Member

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  3. chesapeake46

    chesapeake46 Senior Member

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    Talk about boat porn...........................
  4. DOCKMASTER

    DOCKMASTER Senior Member

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    PacBlue you’re such a tease

    That Hat is as close to same boat as mine as you can likely get. Even similar gen sets. Although I suspect the HAT is quite a bit heavier. Hard to take advertised speeds at face value as most exaggerate somewhat. Interesting how they list cruise speed at 74% load.
  5. PacBlue

    PacBlue Senior Member

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    I would say that those speeds for the 55 Hatt look to be on the optimistic side or at the very least, light load speeds, but knew you would be interested in it as a reference.

    We should start an over/under on your predicted/actual speeds before it hits the water?
  6. Capt Ralph

    Capt Ralph Senior Member

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    Make sure all nut, bolt heads, PTO adapters and all else un-protected hardware is primed and painted now.
    In the bilge it way to late.
    Don't let anybody forget, now is the time for the oil pan/oil drain valve to get installed.


    Boat Porn.
    I have always warned everybody; I like to watch..
    !cid_16c2848d6f159bf193b1.gif
    Last edited: Feb 12, 2020
  7. DOCKMASTER

    DOCKMASTER Senior Member

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    I’ll be happy with 24 kn cruise. Would be great to get 25-26 but 24 would be acceptable. I don’t really care about WOT as long as I get to full rpm. But I would guess 30 to 31 top end.
  8. Donzi 54

    Donzi 54 Member

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    Can't wait to see some more.
  9. mapism

    mapism Senior Member

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    Boat porn indeed, keep us updated as the work goes on!

    BTW, am I right in seeing hydraulic pumps connected to both ZF PTOs?
    If so, what are they for? Hydraulic thruster(s)? Or are you possibly fitting also fin stabilizers?
    Just curious!
  10. Capt J

    Capt J Senior Member

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    If only one engine has a PTO and you lose it, you then only have the other engine and no thrusters. So they generally put PTO's to both and to allow more pumping pressure at idle when you're docking. It is quite possible one is for stabilizers too, but most yachts I run with hydraulic thrusters have 2 PTO's.
  11. mapism

    mapism Senior Member

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    I said nothing against having them on both engines.
    But I didn't expect to find any, on a 54' sportfish.
    At that size, hydraulic thrusters (as well as fin stabs) are pretty rare, this side of the Pond.
  12. DOCKMASTER

    DOCKMASTER Senior Member

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    I originally ordered including the mounting pads on the PTO’s to drive the original hydraulic steering pumps. The Hynautic system had a pump on each of the original Detroit’s. I wanted to keep the two pump set up so I would have power steering when trolling with only one engine running regardless of which engine. Since placing the original order I made a change and have now installed the DC electric powered SeaStar hydraulic system. This will give me power steering regardless of which engine is running and reduces the number of hoses and equipment around the engines.
  13. mapism

    mapism Senior Member

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    Interesting.
    I didn't even think of steering, which I assumed driven by DC electrical motor, as you eventually opted for.
    Are you now going to remove those PTOs before installing the engines, or leave them just in case?
  14. DOCKMASTER

    DOCKMASTER Senior Member

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    The PTO mountings pads (red mounts in picture) will be removed and blanking plates put in place. No sense having unnecessary appendages just sitting there. We will save the mounts in case future needs ever require something to be PTO driven.
  15. Capt J

    Capt J Senior Member

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    Just install a hydraulic bow thruster to go with them@! :D:D:D:D:D
  16. Capt Ralph

    Capt Ralph Senior Member

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    I think DM is a real driver.
    He don't need no stinking thrusters.
    100104~3.GIF
  17. DOCKMASTER

    DOCKMASTER Senior Member

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    Whereas I do consider myself a real driver and don’t “need” thrusters; I’m long enough in the tooth to set my pride aside and embrace the convenience of a thruster. Installed mine about 5 years ago as seen in my thread for that installation back then.
  18. PacBlue

    PacBlue Senior Member

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    I took a quick peak at the numbers and you should see 32 knots WOT and a 25 - 26 knot cruise, 1950 - 2100 rpm as long as the weight does not grow. Will see at Sea Trials :)
  19. DOCKMASTER

    DOCKMASTER Senior Member

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    Thanks PB. What weight did you use? How much weight can be added before noticeable effect? I'm not planning to add a bunch of weight or anything but I was surprised when the prop selection was made how wide the weight range was from Veem. They seemed less concerned about weight and more focused on hull type, length, HP and ratio. If memory serves, I'm about middle of the range they use for boats like mine. I recall their range went something like 6k - 7k lbs above my full loaded weight.
  20. PacBlue

    PacBlue Senior Member

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    I was using 68 - 72,000 lbs. plus the data from the Hatt 55 repower. I would expect your Donzi to have a faster speed potential than the Hatt, so keeping the numbers a bit conservative until you go on trials.