Iron Nails

Discussion in 'Wooden Boat Building and Restoration' started by rattleandbang, Apr 9, 2015.

  1. PAR
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    PAR Yacht Designer/Builder

    Getting the iron out is paramount and a constant battle with these old cheaply made vessels. Iron was used because their life span was expected to be short and the boat's build costs held down.

    I have a set of custom hollow bits I use to remove these types of fasteners. Picture a hole saw without a pilot bit in the center. I drill down, below the bottomed fastener and a quick knock with a hammer and the fastener encased plug comes out. Once a similar species dowel is installed, the frame and/or planking is restored to it's original stiffness and strength. Delicate frames can be a pain, but the iron has to come out.

    Refastening will not restore the stiffness and strength to the frames or planks. The iron sick area has to come out and be replaced by something, that will restore the localized weakness. If you only want a few more seasons out of her, then simply refasten and see how long it holds up. If you want several years or more of service, the iron has to come out.
     
  2. rattleandbang
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    rattleandbang Junior Member

    This is one of those absolutes I've heard over and again on various subjects that drives me nuts. While I sincerely appreciate the writer's intent and experience, it just doesn't follow. First, the original crummy, wasted old fasteners kept this boat together for 70 years in the water. Second, a circular deposit of iron sickness of perhaps 1/8-3/16 in 1 1/2" oak frame hardly renders the frame a write-off. 80% of the remaining cross section of the frame is sound, and to suggest that after screwing planks into that remaining wood the vessel would fall apart in a couple of years simply doesn't bear out.

    Yes it could be restored to original condition, but what's the point other than to give a purist wood (hah)? if it lasts another twenty years would be a miracle, and greatly exceed the original intention, and the needs of any current owner. If I was to honestly restore it in the manner it was built, I would pound a bunch of nails in it, putty the nail holes, apply paint and be done. As it is, I want to securely fasten it, spline the planks, and epoxy the exterior, which is far more extensive treatment the original designers and builders intended. I might even laminate plywood strips over the planks. Not totally sure why, but it sounds nice and strong.
     
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  3. gonzo
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    gonzo Senior Member

    Cold-molding and fiberglassing over are also options. However, making more holes in a weakened structure is usually a poor repair. Also, fasteners were originally located on the ideal location. The refastening places them in a not so good location and in planks and frames that have deteriorated. You could pound a bunch of nails, but that decision shows a lack of understanding of wooden boat structure. You would be better off by drilling most of the deteriorated wood and trough-bolting.
     
  4. rattleandbang
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    rattleandbang Junior Member

    The pounding nails was tongue in cheek. As far as location, because the nails were staggered, it is possible to mirror image them - in the same location but opposite. I agree it's not perfect.

    All of this is experimental, and I understand that. Even in a world of best practices everything depends on a whole host of variables. I don't believe restoring the hull fastening to original condition is worth it. The question is what will be good enough? I've thought about through-bolting but that too smacks of excessive. Once the hull is splined it becomes somewhat of a monocoque structure, and nobody can say just what degree the frames are even needed at that point. They are still required, but not as much. Which also suggests fastening method becomes less critical.
     
  5. gonzo
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    gonzo Senior Member

    Splines may break fasteners of make the planks come loose. It has to be done cautiously. The amount of pressure softwood splines can create is huge. They should only be used when the seams are too wide or open all the way through. Otherwise, cotton or oakum are the proper materials for the job.
     
  6. rattleandbang
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    rattleandbang Junior Member

    The planks are dry and wide open especially below the wl. My biggest concern is the keel as it's a great slab of oak that has dried to the point of opening up the joint with the stem, and from what I understand oak moves a lot compared to fir with moisture, and since I'm going to make the hull dry with splicing and epoxy, if I spline to the keel (which I won't epoxy) I'm afraid the keel will crack the garboards as it swells.
     
  7. gonzo
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    gonzo Senior Member

    It will certainly crack if you epoxy splines. Seems like that hull is in worse shape than what you originally described. The best thing you can pay for now, is an inspection by a wooden boat carpenter or surveyor.
     
  8. PAR
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    PAR Yacht Designer/Builder

    Get a garden sprinkler, the kind that sweeps in a rainbow arc that kids like to jump across and place it (them) under boat, so it can sweep back and forth on the planking and keel. In a few days, she'll start to swell up and the seams will look a lot better.

    Of course you do this after you've insured the structure is sound enough, to accept the edge set, the planking will pace on it when it "takes up".

    Refastening is an option, though a traditional refastening would use the same, restored holes, though making new ones can and does work, assuming the structure is sound enough to accept the additional holes. Most work boats can take this treatment, though yachts often are too dainty to tolerate this approach.
     
  9. rattleandbang
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    rattleandbang Junior Member

    Actually the drying is deliberate as I want to epoxy spline the planks rather than caulk and putty. I need to remove the ceiling to get a clear view of all the ribs but what is visible so far looks pretty good with only a few cracked. They are 2X1 oak which leaves a lot of space for additional fasteners.

    But I've been told that oak doesn't hold epoxy well, so hence the problem of how to deal with a dry hull while allowing the keel to get wet. I've heard of encapsulating it with ply and wrapping the ply in cloth. That way all the wood stays nearly dry as it is now with minimal movement.
     
  10. gonzo
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    gonzo Senior Member

    Mix and matching systems is a perfect recipe for disaster. If you spline the seams and they have no give, when they swell they will crack the frames and break fasteners. If you are going to cold mold over it, then there is no need to spend time splining. Thickened epoxy will fill the gaps. You will have to epoxy the inside too to prevent the wood from absorbing humidity and swelling. Looks like you don't have a clear understanding of wooden boat structures. It will save you a lot of time and money to hire a professional to make a plan for you. Then, stick to the plan and don't start changing it each time someone has a different opinion. Many techniques work as long as you start and finish with the same.
     
  11. rattleandbang
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    rattleandbang Junior Member

    And everything I've heard and read is you don't try to encapsulate the interior or you get rot. You encapsulate the outside to keep water out, but leave the interior to breathe.

    Also the point to splining and coating with epoxy is to keep the planks from absorbing water and swelling. I'm not at all sure about cold molding the entire hull and if I did, yup, I wouldn't spline, although it makes a stronger hull. All I said was essentially cold molding the keel so epoxy and cloth has something to bind to; that's not a different system, its overcoming a problem applying epoxy to oak. I don't want the keel to absorb water and swell if I do the splining and epoxy job to the hull.

    I'm wondering where all the disaster talk is coming from as I've done pretty extensive research and talked to a lot of people. Probably just communication. I do know that if I want to have a dry hull, all components must be kept dry. If wet, everything must be wet. I do know about differing expansion rates of different woods.
     
  12. gonzo
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    gonzo Senior Member

    Have someone explain how can the spores germinate with no humidity. It is a proven fact that fungi, bacteria and yeast only reproduce within a narrow range of humidity. Anything above or below and they either die or stay dormant. The "breathing" is just an old wives' tale. Moisture travels mainly along the grain of the wood. It is nothing but a bundle of pipes held together by lignin. There is some moisture migration along the fibers, but it is minimal in comparison.
     
  13. rattleandbang
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    rattleandbang Junior Member

    I know this. Hence the danger of 100% encapsulation which is almost impossible to achieve and so instead you get a situation where water moves in and can't move out. By "breathing" I mean ventilation in which any moisture that does get into the wood is potentially able to evaporate out. Imperfect? Yes. But even in production fiberglass boats you get problems of wood cores rotting because water gets in and it has nowhere to go.
     
  14. WindRaf
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    WindRaf Senior Member

    But the nails are to replace all or only in certain parts?
    Because if it is just some areas, and you don't want from scratch removing the old nails, add new segments sections of ribs next to the old ribs and plant new nails.
     

  15. PAR
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    PAR Yacht Designer/Builder

    Rattle, stop paying attention to whomever is telling you to not encapsulate with epoxy, simply because they're talking out their asss. Testing and long term field trials bare out this fact and have for decades.

    On a carvel, unless you completely remove the planking and it's less than 1" thick, total encapsulation is not practical. The idea of permitting the wood the breath is simply an old wives tail that has no reality in modern wood/epoxy structures.

    Do yourself a favor and log onto both westsystem.com and systemthree.com and download their user's guides and "Epoxy Book", to get a clue about the appropriate techniques employed with wood/epoxy.

    Having restored and repaired many carvels over the decades, I can tell you straight up, the cheapest and easiest way to repair them is with traditional methods, not modern goo's in a can. Strip planking can work, though it adds a lot of weight to the boat, not to mention lots of goo, materials and effort. Spines will add less weight, but often don't work nearly as well as you hope, unless done carefully and properly.

    Lastly, oaks bond fine with epoxy, again, part of the wives tail crap you've been paying attention to, I suspect. In short, there's not fast and easy way to offer a good cure for your boat's ills, but there are several options, each with good and bad things to consider. Applying another hull over the existing one (strip planking or molding) usually costs several times as much in materials and labor, than simply making traditional carvel repairs, plus the weight increase, which you'll pay for at the fuel dock. Spines can work, but the structure has to be sound or they'll tear out in a heartbeat and now you're back where you where, with no hope of pounding in some caulk to fix it. Gluing the planks only works if the planks aren't too thick. If they are (1" is the max for hardwood), internal stresses in the planking will spit out the spines in short order, because the epoxy glue line can handle these stresses, if the stock is too thick. If the planking is softwood, then you can live with 1.25", with some saying 1.5", but it's still pushing it and I never try it on anything over 1" in planking.
     
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