Shaft zincs

Discussion in 'Projects & Proposals' started by goodwilltoall, Mar 13, 2018.

  1. goodwilltoall
    Joined: Jul 2010
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    goodwilltoall Senior Member

    Was ready to order zincs with intention to put a shaft collar (donut) zinc around shaft however, with props being cpp, they move aft and fully pitched there is only 1/2" of shaft available, to short secure one.

    Machined current shaft to match original, now after the fact it could have been lenghtened but this how sabb did it so figured it be ok. Is there some way to still protect shaft?
     

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  2. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    There are low clearance shaft zinks or propnut mounted zinks.
     
  3. CDK
    Joined: Aug 2007
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    CDK retired engineer

    With only 1/2" of shaft exposed, galvanic currents will be so small no extra protection is needed.
    There are threaded cones to replace a prop nut, but I would leave things the way they are.
     
  4. gonzo
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    gonzo Senior Member

    You can install a bigger anode around the cutlass bearing.
     
  5. goodwilltoall
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    goodwilltoall Senior Member

    This assembly has no prop nut, or cutlass bearing. Prop hub has 2 bolts with ss washers you fold back around bolt to prevent pullout, the prop hub also has the thrust bearing, fwd of that is bronze pipe with very close tolerance called a weartube.

    The shaft log is 30" and there are 2 greasing points, one at packing box and one at prop hub (greaser tube from inside) which keeps entire shaft greased.

    Pic shows 1/2" of shaft when pitch is changed there will be 1 1/2" of shaft exposed.

    CDK, want bronze hub and props protected. Someone mentioned sealing with epozy on your thread, what are your thoughts on that now?
     
  6. gonzo
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    gonzo Senior Member

    Whatever it is that hub bolted to the keel, you can install an anode on it.
     
  7. goodwilltoall
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    goodwilltoall Senior Member

    Yes, was thinking that. Counter drill zinc with a lil epoxy on jam nut interface to prevent wear there. Those two bolts on mounting flange extraneous as whole log is embedded in epoxy.

    Maybe you can see on rudder 2 bolts to attach 3" × 4" zinc, hopefully with those two the area in between is protected.

    Rudder is 20" × 28" is it necesary for zincs on each side?
     
  8. exp30002

    exp30002 Previous Member

    Well, just a thought: may be custom made zinc. To melt and pour zinc in the shape of a disc with of 1/4'',
    or reshape the zinc with a hydraulic press to a disc.

    The comment about the small galvanic current is probably right. So a smaller zinc might do the job.
    May be the zinc can be cut to fit.

    Anyways, I said more than I know.
     
  9. gonzo
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    gonzo Senior Member

    You can melt zinc with a camping stove or a propane torch. I suppose it wouldn't be too hard to melt your own anode.
     

  10. goodwilltoall
    Joined: Jul 2010
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    goodwilltoall Senior Member

    That a great idea. I have pc of old shaft to stick in middle of cup with molten zinc then drill hole in middle 4 bolt.

    I was also concerned about the bronze or silicon bronze apeture, have seen pics of them pitted due to galvanic corrosion
     
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