Zincs
Zincs
I have a question on zincs for my '69 Bristol 29. I have very little exposed shaft between the hull and the prop so the past two years since I've owned the boat, I have placed a prop nut zinc. Both times the zinc was gone when the boat was hauled, not sure if it was completely corroded or just came lose and fell off. So this year, I would like to add a zinc collar in addition to the prop zinc. Since I can't find a narrow enough 7/8 collar, I grinded the collar down to fit with about a 1/16 of a inch on both sides between the prop and the hull. Is that okay?
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Re: Zincs
We do it all the time at the boatyard. One might think there would be standard applications for standard zincs, but in reality the word standard has little application at all. The biggest consideration (I am assuming you will do it safely) in grinding /cutting is assuring that the fastening mechanism isn't compromised.DavidL wrote: Since I can't find a narrow enough 7/8 collar, I grinded the collar down to fit with about a 1/16 of a inch on both sides between the prop and the hull. Is that okay?
Dave Finnegan
builder of Spindrift 9N #521 'Wingë'
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Gresham’s Law of information: Bad information drives out good. No matter how long ago a correction for a particular error may have appeared in print or online, it never seems to catch up with the ever-widening distribution of the error.
builder of Spindrift 9N #521 'Wingë'
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Gresham’s Law of information: Bad information drives out good. No matter how long ago a correction for a particular error may have appeared in print or online, it never seems to catch up with the ever-widening distribution of the error.
For a while we were "losing" prop nut zincs like crazy - they wouldn't be worn down, just GONE. Then someone suggested coating the little thin bit that's behind the fastener head; they felt that that bit ate away first which allowed the whole thing to drop off. We started coating that part with nail polish (in retrospect, duh, epoxy would have been better) prior to installation and it seemed to help.
I say it all a bit theoretically because since that part is behind the fastener anyway, I'm not sure if it can erode. There is one little section there that - once it's gone - completely renders the fastener useless.
I say it all a bit theoretically because since that part is behind the fastener anyway, I'm not sure if it can erode. There is one little section there that - once it's gone - completely renders the fastener useless.
Prop shaft zinc
I also have a B29 and use a 7/8" collar. I suppose my shaft protrudes a bit more than yours since I don't have to shave it down.
David
David
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Rachel wrote:
What am I am talking about? Well I have been scratching my head with my prop nut zinc the last two haul outs (both cases gone). I just figure it was completely sacraficed. Now it all start to make sense to me. I also contemplated with adding a 7/8" collar zinc but there just was not enough space there. I never even thought of shaving it down. Well now Triton106 is back in the water it is too late until my next haul out two years from now. Thanks... sigh.
I don't know why this keeps happening to me but I search all over internet to find a particular subject matter (eg. how good is Interlux Brightside for painting hull using roll and tip method) but could not find it but the minute after I complete the project (eg. bought 6 quarts of Brightside and primer) the subject comes to me without my asking.For a while we were "losing" prop nut zincs like crazy - they wouldn't be worn down, just GONE. Then someone suggested coating the little thin bit that's behind the fastener head; they felt that that bit ate away first which allowed the whole thing to drop off. We started coating that part with nail polish (in retrospect, duh, epoxy would have been better) prior to installation and it seemed to help.
I say it all a bit theoretically because since that part is behind the fastener anyway, I'm not sure if it can erode. There is one little section there that - once it's gone - completely renders the fastener useless.
What am I am talking about? Well I have been scratching my head with my prop nut zinc the last two haul outs (both cases gone). I just figure it was completely sacraficed. Now it all start to make sense to me. I also contemplated with adding a 7/8" collar zinc but there just was not enough space there. I never even thought of shaving it down. Well now Triton106 is back in the water it is too late until my next haul out two years from now. Thanks... sigh.
Ray D. Chang
Triton 106 in Berkeley, CA
Triton 106 in Berkeley, CA
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Maybe, but this tangent is getting a little carried away from the topic of zincs and I really don't think the rays in San Francisco Bay compare with what I agree are certainly more dangerous Australian sea species. For the record I have dived with thousands of Australian rays when I lived there with no hint of danger or aggresion on the ray's part. Don't mess with them, they don't mess with you. What happened to the Croc Hunter was a truly freak accident which could probably have been avoided if he had left the damn thing alone in the first place. Makes for boring TV though. In my experience, real croc hunters despise the late TV personality and often redicule him.Along with the box jelly-fish, great white sharks, salt water crocs and blue-ringed octopus......
Point being, if you can combat the cold using an inexpensive rented wetsuit, you can work on the zincs in the water.
Point taken. Back to the zincs falling off.... I've seen zinc collars fitted with two hose clips (worm gears on each side for balance I guess) in addition to the metal threads supplied with the collar. Sometimes the collars on my boat disappear within a few months, other times they are almost untouched after a year.bcooke wrote:Maybe, but this tangent is getting a little carried away from the topic of zincs and I really don't think the rays in San Francisco Bay compare with what I agree are certainly more dangerous Australian sea species. For the record I have dived with thousands of Australian rays when I lived there with no hint of danger or aggresion on the ray's part. Don't mess with them, they don't mess with you. What happened to the Croc Hunter was a truly freak accident which could probably have been avoided if he had left the damn thing alone in the first place.Along with the box jelly-fish, great white sharks, salt water crocs and blue-ringed octopus......