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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. PacBlue

    PacBlue Senior Member

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    Looking good, you sized the shaft lengths nicely to maintain the right gap length between the fwd prop hub face and aft strut barrel face.
  2. rtrafford

    rtrafford Senior Member

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    You've gone through all fo the right stuff here in terms of the scope of your project, but noting, have you dropped your rudders? I wish I had last fall........just sayin....
  3. rtrafford

    rtrafford Senior Member

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    Also I tried a trick last year, and I used prop speed on the bottom of my trim tabs instead of bottom paint. Thus far working well.
  4. DOCKMASTER

    DOCKMASTER Senior Member

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    I had the rudders out not that long ago and repacked everything. We did do NDT of the welds where the blades attach to the post and all was good.
  5. mapism

    mapism Senior Member

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    I was actually wondering if those blades are OEM: they look unusually long to me.
    But I'm only comparing them against the prop shaft height, not vs. other SFs - let alone the Donzi 54 specifically.
    Maybe that's normal in SFs, for granting a better maneuverability at low speed?
    Regardless, I can't think of any logical reason for that very low anode position on the blade.
    Impressive job overall, anyway!
  6. DOCKMASTER

    DOCKMASTER Senior Member

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    Rudders are original to best of my knowledge. Actually the large rudders were a selling point for me when I bought the boat. We do lots of hours very slow trolling on only one engine. The larger rudders make this much easier.
    The rudder anodes are where they were originally. I didn’t see any reason to drill another and move them. What would be gained by moving? Maybe a small reduction in erosion at best?
  7. Donzi 54

    Donzi 54 Member

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    Your rudders are the same as my originals. Although I replaced them with the newer hatchet design that Roscioli is using now. I'm curious, is a zinc needed on the rudders? I never had a zinc on the rudders or the shafts. I was told that the two large hull zinc plates on the transom where all that was needed, being that everything was bonded to them
  8. Capt J

    Capt J Senior Member

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    If you don't have a bonding wire going to the rudders inside of the boat, then yes, you should have rudder zincs.
  9. DOCKMASTER

    DOCKMASTER Senior Member

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    I’ve had issues with zincs since I got the boat. I would lose most of a shaft zinc one side but not the other. Some with rudder zincs. We went to two zincs per shaft. We always attributed it to boats around us given the wide variance of boats in our marina. However, as we got things torn apart for the repower and were checking everything we found the bonding system in the lazarette was pretty suspect. All has been replaced now so I’m curious to see how we fare going forward. I plan to put one zinc per shaft and rudder and will monitor closely.
  10. Donzi 54

    Donzi 54 Member

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    I had a similar issue were the starboard trim tab zinc would not last a full year compared to the port side. The bonding wires in the lazarette was in need of replacing. After totally replacing all the bonding wires, ground terminal blocks and replacing the two 50amp galvanic isolators from the lazarette to the engine room. I now only need to replace the to zinc plates and they now even wear less. The bonding wires are often very much over looked and need maintenance.
  11. mapism

    mapism Senior Member

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    Well, I was only wondering because most of the rudder anodes I've seen were further up, much closer to the hull.
    But to be honest I don't think that can make any meaningful difference, and I surely wouldn't bother drilling another hole and close the existing one.
    If it ain't broke, etc.

    I wouldn't feel comfortable relying on the transom anodes alone as D54 said, though.
    Of course, the "if it ain't broke" principle still stands, but you never know: anodes can be more or less necessary depending also on where the boat is moored at any point in time, not just on the boat itself.
    In the example below, everything is bonded to the big round transom anode along the centerline, rudders and shafts included.
    But also the specific anodes still wear out a bit. And if nothing else, they are a safety net, so to speak.
    I mean, bonding wires connected to moving parts can be not as effective as other bondings, like those to seacocks for instance.
    BTW, the pic below shows also anodes on top of the prop nut.
    I've often seen them used as an alternative to shaft collar anodes, and I can confirm that they work well.

    [​IMG]
  12. Donzi 54

    Donzi 54 Member

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    I'm on the side that over protecting a boat is a mistake if not necessary. A good topic for another thread.
  13. rtrafford

    rtrafford Senior Member

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    I agree. Spread the protection and protect the protection. It's a solid general rule. Heck, it also helps you understand where to begin to look when a problem appears.
  14. mapism

    mapism Senior Member

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    Not disagreeing with the general principle, but for shafts and rudders, I think your boat is actually more an exception than the norm.
    Coming to think of it, I can't remember to have seen any boat with neither shafts nor rudders anodes.
    In fact, in both cases, dissimilar metals are widely used in these components - like s/steel and bronze, but not only.

    Besides, no matter how good the bonding, if nothing else it's a helluva long way to reach your transom anode plates, at least from the props.
    In fact, anodes should be not only properly bonded, but also placed within 3 feet or so from whatever component they are meant to protect.
    So, you can see why I wouldn't consider shafts and rudder anodes an "over" protection.

    Mind, 3 feet is just a rule of thumb, and I'm not suggesting to take it religiously - btw, since I'm used to metric, I normally refer to 1 meter, which is actually a tad more.
    But relying only on the transom anodes necessarily implies a MUCH longer distance.

    By chance, did you ever measure the resistance between the props and the transom anodes?
    If you never did, in your boots I'd take the first opportunity when the boat is on the dry for a very easy check:
    Just connect a multimeter to the transom anodes on one end, and to a prop on the other hand.
    If you will read more than one ohm, you'd better add some dedicated anodes.
    And if you will read less, I'll eat my hat! :)
  15. Donzi 54

    Donzi 54 Member

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    No I have not checked the resistance with a ohm meter, don't know if that would be accurate anyway. But I do check the underwater metals with a multimeter and a silver-chloride electrode set to millivolts. Very easy to do while the boat is in the water. If I am not mistaken that is the way it should be done.
  16. mapism

    mapism Senior Member

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    Wow. It's not so common to hear of that on a pleasure boat, let alone a plastic one.
    Sorry if I was teaching you how to suck eggs.
    Out of curiosity, what sort of readings are you getting, and how did you determine your baseline?
  17. DOCKMASTER

    DOCKMASTER Senior Member

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    Not a whole lot to report as progress has been very slow due to COVID-19 impacts. My project lead was out for several weeks as a precaution and my electrician has been out for a month and counting. Virtually everything in the engine room is done as far as we can go while we wait on the exhaust and remaining electrical. The exhaust is en route but taking awhile to get across country and up to Ketchikan. Hopefully we will have it in a week or so. Once the exhaust goes in we can final install the fuel Racors on the port side and the two refrigerator/freezer compressors that mount on an overhead foundation in the aft port corner of the e/r. There just isn't enough room to reasonably get to the exhaust if these items were installed. Progress is being made on the interior joiner work and the aft bulkhead access cut and window are finished with only one final coat of paint to go on the outside. All new and relocated components are in their final home on the bridge console just waiting for electrical connect now. A future project for next year will be to glass in and re-paint the bridge console. It looks like a bit of a patch work quilt with all the panels but it will have to do for now. Main focus currently is to get everything done in the salon so we can turn it over to have the headliner installed and the new carpet put in. We are aiming to splash on or about 5/18 but that may be optimistic. We want to finish as much as we can while it is convenient to work inside and access is simple. If we do get wet on 5/18 we still have much to do but at least we would be able to start testing new and disturbed systems.
    As much as I want everything done and am anxious for trials their are just too many issues out of our control to know when we will finish. We didn't come this far to start cutting corners now so I have wrapped my head around the notion that it is what it is and it will be finished as soon as reasonably possible and without putting folks at risk.
  18. PacBlue

    PacBlue Senior Member

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    Nice to stick to your plan and do it right, probably a trickle down approach from your shipyard business, good on you.

    I had a 48 Egg Harbor Flybridge project way back when, similar in that it needed a redo and had a lot of old stuff that was cut in and looked funky. Realized it was easier to build an aluminum console in the shop, lay it out the way I wanted it, had all the right cut-outs and ergonomics, painted it in the shop, then just cut and pasted it in place, everything went together real well and it did not take a lot of downtime.
  19. DOCKMASTER

    DOCKMASTER Senior Member

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    I don't think an alum console will work here but it is a good idea. You can see the patch panels we're using in the below picture. This will do for now. I think next winter we will glass in all the holes, re-paint the black and start over. This will give me an opportunity to lay-out items exactly as I want them. We also could benefit from having the 3(ea) Simrad screens mounted without a panel which will require a short height extension where they go. One Simrad is to port and the other two mount in the opening shown to Stbd. The two stbd screens are out for easy access behind for all the electrical we have to do.

    We changed things up quite a bit from the original plan. The small screen between the CAT panels is the ZF data display. We originally had it and the ZF back-up panel right in front of the engine controls. And we had the 3 fuel gauges between the CAT displays. The ZF back-up panel is now to Stbd and is the one with two dials on it. And you can see where the fuel gauges are going. You cannot see the thruster control in this picture, it is to port of the engine control levers.



    IMG_3716.JPG
  20. DOCKMASTER

    DOCKMASTER Senior Member

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    Electrician is back finally! Two days of electrical progress and building momentumOrdered 6x Group 27 Full River AGM batteries for house bank. This will be 2 more batteries then before. Happy to have the extra battery capacity.
    All joiner work on aft bulkhead done and varnished and window is back in. A/C valances have new upholstery and installed. Port settee is going in tomorrow. Headliner replacement scheduled for 5/11 and new carpet install on 5/18. Tentatively scheduled to splash on 6/2 and commence testing.

    I saw a YouTube video yesterday claiming a 57’ Spencer with 1000 hp C-18’s does 28 knots at 1800 rpm burning 67 gal/hr and top speed of 38 knots. Even if the 1000hp was a mistake and they are 1150’s like mine how are those speeds possible? Surely this is an extreme exaggeration? I don’t expect to see anything near that and I’m only 54’. Is a 2013 Spencer hull really that more efficient?