"Sistering" keel bolts on my Islander 28

Discussion in 'Fiberglass and Composite Boat Building' started by Downeast450, May 17, 2010.

  1. Downeast450
    Joined: May 2010
    Posts: 18
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    Location: Seal Harbor, Maine

    Downeast450 Junior Member

    I have decided to add 4 "sisters" to the keel bolts in my Islander 28. I do not like the condition of the exposed bolts. They ring true. The threads above the nuts are rusted to the point that they could not be engaged by the nuts if I backed them off. There is no leak associated with the keel. A visible seam is present but no latent wetness after hauling. What worries me most is the amount of lead visible in the bilge. The only place lead is not visible is under the washers. IS THAT NORMAL? There is copious "sealant" around the perimeter of the stub. I was planning to eliminate the original knot meter's thru hull that was moved by a PO from the side of the keel to a spot just above the turn of the bilge. It has a plug living there now. Considering the glass work involved with that and the anxiety surrounding the condition of the original bolts I decided to spend a week and lay up enough new glass structure to support sisters. It is a big job and I will be removing and replacing the bilge frames one by one as each location is prepared. I have the tools and experience to do the modifications to the hull. What I don't have is any experience with keel bolts!

    Now I am deciding on the material for the new bolts. Any suggestions? SS seems logical but it will be encapsulated inside the keel. I am thinking of 1.25" or a little larger steel. Since I will be building the bilge beds for these new bolts I can raise them a bit higher that the originals to keep them out of any bilge water. The originals are steel and have lasted in terrible conditions since 1977.

    I have a good laminate schedule including Kevlar but wonder if I should build in a steel shoe at each new bolt location and how far it should extend laterally?

    I expect that when all the glass work is complete I will have covered the inner surface of the keel completely. I have to decide how to treat the existing bolts. I am thinking that a good wire brushing and then just work the new laminate around them can't hurt.

    To keep the work area free of styrene I will be using System Three laminating epoxy resin. I plan to drill the holes in the lead before doing the glass work. I have practiced drilling into lead. That can be tricky and I welcome your suggestions. I will plug the holes with a piece of wood for the glass work and remove it when I am ready to install the bolts.

    I will alternate sides for cutting the slots into the keel for the lower nuts and washers.

    All comments are most welcome.

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  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Modifying a structure to the degree you mention can cause all kinds of problems. You seem pretty unclear about the changes while you claim to have the experience to do the job and figure out the changes. I would suggest to change the bolts if needed, but leave everything as original.
     
  3. Downeast450
    Joined: May 2010
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    Location: Seal Harbor, Maine

    Downeast450 Junior Member

    Thanks Gonzo,

    I appreciate your warning. I am not concerned that what I intend will create any new problems. As I look into the bilge I am seeing the top of the lead keel and not a "shoe" or floor in the stub. The only purchase enjoyed by the existing bolts seems to be whatever is immediately below the keel bolt washers and anything that remains lateral to their location. Bare lead is what shows in the spaces between the 3 pairs of bolts and the solitary one at the forward end of the keel. I am amazed that the 3K of lead is still attached and that I have no leaks. The "sealant" that shows around the stub's perimeter must be contributing a lot to more than keeping things water tight.

    What I intend is the sistering technique described by Don Casey in http://www.sailnet.com/forums/gear-maintenance-articles/19871-keel-bolt-repairs.html

    Since there is nothing to drill through in the bilge except the lead I will need to layup an internal floor in the stub that can help support the keel. The possibility of removing the floor frames is to give me room to do this work and I am sure they can be put back with the same integrity, or more, than they currently have. They are wooden frames that are glassed in and covered with glass. Drilling into them reveals their wet, punky condition. I intend to replace them with new wood when I put them back.

    What are your specific concerns? I can not replace the existing bolts without building a new floor for the stub and that is basically what my plan intends. If I were to drop the keel now I would not have anything to reattach the keel to anyway. I imaging being faced with supporting the repaired keel as I built a floor in the stub to bolt it to.

    I am thinking that four 1" Aquamet 22 bolts will provide enough additional support to allow me to sail away with confidence. The job is building up the floor of the stub to carry their contribution.

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  4. apex1

    apex1 Guest

    And use galvanized mild steel instead of SS !
     
  5. Downeast450
    Joined: May 2010
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    Location: Seal Harbor, Maine

    Downeast450 Junior Member

    Apex1,

    I may end up with galvanized steel but Don Casey's approach, if done with the proper care, seems to address the ss corrosion problem.

    Thanks,

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  6. apex1

    apex1 Guest

    Do┬┤nt know about that "approach" but I am very careful with SS installations. Keelbolts should be of Monel, Bronce or mild steel imho, but never SS.

    Regards
    Richard
     

  7. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Those metals are the best. Aquanet is prone to crevice corrosion.
    Can you drop the keel and replace the bolts?
     
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