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al brazzi
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2,088 Posts
Discussion Starter · #1 ·
Keel Nuts

While investigating the rusty areas around the Keel nuts they are worse than I could have imagined. All will be replaced. On my CS30 the plates (washers) under the nuts look to have some packing between the plate and the stud surely its there for a reason could someone enlighten me. The studs seem intact with no issues at all but I don't like the way the nuts look, could I have some dezincification happening here. I have no indication they are anything but original would the wrong anti-seize contribute to this. I will go with the best grade my bolt guy has available, is there a particular one that should be used.
Glad I checked my nuts.
 

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al brazzi
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2,088 Posts
Discussion Starter · #2 ·
While investigating the rusty areas around the Keel nuts they are worse than I could have imagined. All will be replaced. On my CS30 the plates (washers) under the nuts look to have some packing between the plate and the stud surely its there for a reason could someone enlighten me. The studs seem intact with no issues at all but I don't like the way the nuts look, could I have some dezincification happening here. I have no indication they are anything but original would the wrong anti-seize contribute to this. I will go with the best grade my bolt guy has available, is there a particular one that should be used.
Glad I checked my nuts.

Update already; New 304 18-8 nuts on hand changing out tonight. Boat is new to me in September concerned about stray currents at this point but it may be a long coming issue, nuts were rusty and noted on survey but none pulled. I will check my engine zinc and haul and check shaft zinc as well depending on what I discover the next couple of days. will be moving to a new slip as soon as the one I want is available since I am soft grounded at an abnormal low tide in case that could be a factor.

Thanks AL
 

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CS used a Tremco sealant for many years on the keel to stub joint, silver/grey in color. I never did this job in the plant so not sure of specific product but I know it came in 5 gallon pails and was not a 2 component sealant. Tremco also supplied the butyl tape for hull/deck joint, hardware bedding.
 

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al brazzi
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2,088 Posts
Discussion Starter · #4 ·
CS used a Tremco sealant for many years on the keel to stub joint, silver/grey in color. I never did this job in the plant so not sure of specific product but I know it came in 5 gallon pails and was not a 2 component sealant. Tremco also supplied the butyl tape for hull/deck joint, hardware bedding.
Any thoughts on the nuts they are pretty ugly!!
 

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Old enough to know better
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Re: Keel Nuts

I would think there woudl be some bedding compound under the plate to even the pressure out, and be a last ditch effort to stop water from coming in. Seems the nuts should be of the same material as the keel bolts, I would think they were some sort of stainless, likely some form of 3XX stainless. I think you should try to post some photos, as it sounds like it may be electrolysis, you may have some stray currents running around.
 

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al brazzi
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2,088 Posts
Discussion Starter · #9 ·
Re: Keel Nuts

I will try and post some photos. Electrolysis for sure. The worst ones are where the two side by side bolts that share a backing plate, there was a comment on another post referring to this arrangement and how it was not recommended, might be just an opinion but I know how current potential works and I am going to separate the backing plates to eliminate this and I now wonder if tying two studs to the each other is somehow adding to this. All the nuts are replaced now and it will be a regular check for me for a while anyway. Checking all the other zincs since this is a 25 year old boat and I have only owned is 4 months I don't know if this has been coming on for a long time.
 

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al brazzi
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2,088 Posts
Discussion Starter · #10 ·
Bolts (studs are clean as a whistle, what I've heard is the damage is usually under the nut so not sure what course to take right now. Any thoughts on bolts sharing a backing washer? the side by side bolts (stud) nuts tied by the backing plate were the worst ones by far. What I know about electricity is one bolt and nut may be a post but two tied together is a circuit or at least potentially, when there is a lead bulb involved also.
 

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I'm about to buy Nicholson 33 1976
Between the hull and the keel there is a crack (Not resulted from grounding)

I'm planning to haul out, separate the keel from the hull and change the nuts.
Does any one knows if this model has lead or Iron keel?
Any info about the nuts. Are they cast in the keel (J shape)
or threaded.

Thank you!
 

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Learning the HARD way...
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7,834 Posts
If a magnet sticks to the keel, then it is iron. If not it may be lead (or encapsulated).
 

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al brazzi
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2,088 Posts
Discussion Starter · #15 ·
If there is a nut then its a stud into the body, most probably lead. If its encapsulated there are no fasteners. Most are lead, Bandeau's are usually Steel and fasten differently, there are posts that cover that better, I wouldn't even try. The nuts can be easily changed without dropping the Keel, one at a time if you're in the water!!! dropping to inspect is always better but you better check with the yard you are planning on using, most will not want to drop a Keel its a big deal relatively speaking. My last two boats had a "crack" if you want to call it that. Its the Keel joint and will tighten up while on the ground with the weight of the boat on it with the attachments serviced properly, basically squeezing the bedding out as you tighten, sealing and fairing may be needed as well but start with this.

Probably the most important service you will do on a used boat, the consequences are just too big.
 

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If there is a nut then its a stud into the body, most probably lead. If its encapsulated there are no fasteners. Most are lead, Bandeau's are usually Steel and fasten differently, there are posts that cover that better, I wouldn't even try. The nuts can be easily changed without dropping the Keel, one at a time if you're in the water!!! dropping to inspect is always better but you better check with the yard you are planning on using, most will not want to drop a Keel its a big deal relatively speaking. My last two boats had a "crack" if you want to call it that. Its the Keel joint and will tighten up while on the ground with the weight of the boat on it with the attachments serviced properly, basically squeezing the bedding out as you tighten, sealing and fairing may be needed as well but start with this.

Probably the most important service you will do on a used boat, the consequences are just too big.
Thanks you!
It is defiantly going to be my first investment in maintenance.
 
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