Sistering in Keel Bolts

Discussion in 'Boat Design' started by CharlieDanger99, Jul 20, 2021.

  1. CharlieDanger99
    Joined: Jun 2021
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    Location: Tampa Bay

    CharlieDanger99 Junior Member

    Hello, I am considering adding some extra keel bolts to secure the external ballast on my 1960 Rhodes Swiftsure project boat and am hoping for some general thoughts/advice on my situation and plans. Last summer when I removed the rudder, I found the rudder shoe to have been severely damaged by galvanic corrosion. When knocking out the pins that secured it, a crack developed along the port side and it split pretty much in two. Naturally, I'm worried about the condition of the rest of the bronze hardware. I haven't yet opened the rudder, but the exposed parts of the stock look to be in good condition, and a light sanding seemed to remove all of the pink chalky material. The centerboard (1/4 inch bronze plate) is in slightly worse condition, but I've taken a hammer and chisel all around and the corroded areas don't appear to penetrate as deep as on the rudder shoe, and no cracks or otherwise serious damage is apparent. Unfortunately, the pin on which it rotates is cast in to the lead ballast, so I can't remove it to inspect. From what I can see though, it appears to be at least a 3 inch diameter bronze rod, so if the condition of the rudder stock is any indicator, it ought to be acceptable. I would still like to replace the lifting cable with something like dyneema so that if the pin ever does fail I can simply jettison the board. What is of a bigger concern to me though are the bronze bolts that secure the ballast keel to the bilge. The lead pig is split down the middle on the aft end and forms the lower half of the centerboard trunk, meaning that the sealing edges inboard are inaccessible. If this seal has failed at any point in the last 60 years, then the bolts would have been exposed to the water. I suspect that this structure is well overbuilt, but losing the ballast at sea could easily be a death sentence, so for peace of mind I am leaning toward sistering in some extra bolts. I imagine drilling through from the bilge and dropping in some bronze threaded rod, countersinking the nuts/washers into the bottom of the lead and covering with thickened epoxy, and finishing with glassed over nuts/washers in the bilge. I don't have the means to separate the ballast from the boat so I believe this would be the best option. I would certainly appreciate any resources to help me figure out a good plan of action. The original bolts are the J-style, cast in to the lead, with glassed over nuts in the bilge. I would like to minimize the number of holes I have to drill and could use some info on selecting the correct diameter of bolt. I would also gladly take any tips for the actual drilling process, ie the right machine, bits, etc.
     
  2. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    For anybody who is not familiar with the Rhodes Swiftsure class, here is some useful information about her -
    https://sailboatdata.com/sailboat/swiftsure-33-rhodes

    Charlie, would it be feasible to get your keel bolts x-rayed?
    I do not know anything about this, and I have just been googling it, and (as always) there seems to be lots of opinions for and against doing this.

    If I understand this correctly, - would you drill holes all the way through the bronze keel and attach the washers and nuts at the other end?
    How deep is the depth of keel that you would have to drill through?

    Re how your existing bolts have been glassed over, is this a substantial layer of glass, or would it be feasible to remove it?
    It might be worthwhile removing it (if possible), to see what condition the nuts and washers are in?

    I was going to suggest that you post some photos, although there probably is not a lot to see if the nuts are glassed over - but some general photos of your fine Swiftsure would always be welcomed, as well as any photos that might help to illustrate your problems.
    Re how your original rudder shoe split into two sections, what type of repair did you effect here?
     
  3. CharlieDanger99
    Joined: Jun 2021
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    Location: Tampa Bay

    CharlieDanger99 Junior Member

    I suppose x-raying would be an option, but if it is more expensive than the cost of the bronze rod I think I'd rather just go ahead with the project and have that security.

    Yes I would be drilling straight through the fiberglass bilge floor and out the bottom of the lead ballast. I would recess the bottom nuts into the lead to keep a fair surface. The ballast tapers from about a foot and a half thick (top to bottom) on the leading edge, down to a few inches on the aft ends, with the majority of the weight in the bulbous section forward of the centerboard, directly under the mast.

    I can certainly grind away the encapsulating glass on a few of the nuts to have a look. I will post some photos when I do, but I would still be concerned even if they are in good condition. The rudder shoe had no obvious sign of deterioration until I started messing with it. As for that, I am looking in to a few solutions. I plan to pick up welding to make some other custom hardware for the boat, or I may glue the existing shoe back together to make a mold for casting a new one. I have all of the original seacocks and I was already thinking of melting them down to do some bronze casting projects, so this would be a good opportunity for that. And if I can't manage to get a good result I can always have a machine shop mill one out of a solid block.

    I will get some photos up as soon as I can.
     
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  4. Rumars
    Joined: Mar 2013
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    Location: Germany

    Rumars Senior Member

    If you have enough space to consider countersinking the bottom of the ballast you have space to drop it. Simply jack the boat up with the ballast attached, put some carjacks under it, undo the nuts and lower the jacks. The hull remains on its stands and the ballast comes down. Then you slide it out from under the boat on rollers. You might have to use wedges to break the bond of whatever they originally put between ballast and hull.
    There are essentially two ways of replacing J-bolts, drill out the originals until you hit lead, then chisel a pocket from the side for the nut, or drill trough. The decision to drill out the original or install a bolt in a different location depends on how the internal fiberglass structure is arranged. The new bolts should be the same size or bigger, threaded only at the ends for the nuts.
    The centreboard pin comes out in a similar way, chisel a hole from the side (may already be there, just filled and invisible), drill the pin, replace.
    Any pink bronze needs to be replaced, sanding the pink part away is no solution, pink means the zinc was leached away, you have no way to tell how deep this goes, the parts are scrap.
     
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  5. CharlieDanger99
    Joined: Jun 2021
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    Location: Tampa Bay

    CharlieDanger99 Junior Member

    I have considered this but it is a bit of a scary proposition for an amateur DIYer. How might I support the boat while lowering the ballast? Any examples you can point me toward? Also, there is no additional structure supporting the bolts, the bilge is solid flat fiberglass and the bolts poke through at equal intervals, hence why I'm thinking I can simply add more between the existing ones. Additionally, I don't see why I wouldn't be able to drill out the centerboard pin with the ballast attached, especially if there is already a hidden pocket. I'm sure that lowering the ballast would make the drilling work easier, but it's one of those things where one mistake could cost me the whole boat and potentially my life, so I'd prefer to avoid it if possible.
     
  6. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    It makes no sense to replace the bolts if you don't have to. You support the boat with stands, and you can add supports forward and aft where the ballast ends. The scary part is actually lifting with jacks, you do it slowly and check often. Or, if you want to you can build a pair of frames and lift her with slings, or simply hire a crane and put her on higher stands.

    Lifting begins at min 12.
     

  7. CharlieDanger99
    Joined: Jun 2021
    Posts: 9
    Likes: 1, Points: 3
    Location: Tampa Bay

    CharlieDanger99 Junior Member

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