Iron Nails

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

  1. rattleandbang
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    rattleandbang Junior Member

    Funny replys. I do have the Gudgeon's booklets and have read them through. I've also got The Big Book of Boatbuilding, Buehler's backyard boatbuilding for the 21st century (he's the dude that insists epoxy doesn't bond well to oak), and Wooden Boat Renovation: New Life for Old Boats Using Modern Methods. Several people have said these are the go-to books for doing the kinds of repairs I'm considering.

    I get the feeling people aren't even reading previous posts: I said that total encapsulation is nearly impossible; everything I've read agrees with this. I've also read several sources that says to encapsulate the water side and leave the other side open (including Gudgeon).

    I've not actually taken a measure of the hull planks (I'm going to start tearing it down in a couple of months) but at most they are 1X5" fir.

    But despite the teeth gnashing I do appreciate the advice. The below WL seams on this boat are wide open because the hull is dry; it's how I received the boat and I've dried it even more in prep for splining. I really don't know how well the seams will seal if I pull it out of it's bag and let it take up moisture again. I live on Vancouver Island so getting the boat wet isn't a problem.
    The biggest reason for considering splining or cold molding and coating with epoxy/glass is I really don't want the ongoing maintenance of a traditional hull; one of my previous boats was glass over ply, and that worked very well and the boat was over 35 years old.
     
  2. PAR
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    PAR Yacht Designer/Builder

    Unless George has updated his boatbuilding book, it's a product of the 1980's and his views on epoxy (oak included), just aren't verifiable with industry testing and long term (decades) studies.

    Encapsulation is just as the word suggests, you embalm the piece(s), otherwise it's simply painting with a costly plastic. The whole point (encapsulation) is to lock down the moisture content, so environmental changes, don't cause the wood to move. If the wood doesn't move, it's not going to pull at it's fasteners and egg out their holes, assuming a sound structure.

    Again, carvels need to have their planks removed (easy) for encapsulation. While you're there, you might as well epoxy the faying surface on the frame faces too. This is a big job, though if redoing planking, scabbing bits on the hood ends, repairing butt blocks and fixing egged out fastener holes, removing every other plank isn't an uncommon thing to see.These would get the embalming treatment, while the holes and frames where addressed. Once rehung, the other set of planks would get pulled and similar performed. This is a lot more trouble than simply fixing the ills of the carvel, but does make a much more water tight hull.

    If you really want to go low buck, just refasten and coat the hull with truck bed liner.

    Cavels are what they are and making them into something else is possible, but usually, it costs a lot more in time and materials to do so.
     
  3. rattleandbang
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    rattleandbang Junior Member

    Well, the book was updated for the 21st century as the title suggests.

    It's more than simply returning the vessel to service; it's also about minimizing long term maintenance. I've owned a wooden boat of about the same size and remember that:

    1) lousy repairs never last but come up again and again and again...
    2) Old wood, clapped out wood, is very unstable. You finish it nice, and it cracks. You repair it, it cracks.

    The least hassle part of the boat was the fiberglass skin over the plywood hull.
    It was a 30-year old Thunderbird built with 1/2" fir ply coated in polyester fiberglass, and although the glass no longer adhered to the hull, it kept the wood dry. That was a great little sailboat that was a fantastic sailer. I'm not sure why a similar treatment shouldn't work with a stinkpot that doesn't have to bear the loads of a rig.

    Once this is complete I want to enjoy cruising in it, with the odd brightwork varnishing and hauling out every two years as my biggest concerns. Which is why I'm considering coating the hull with either veneer, ply, or fiberglass.

    Is there a rule of thumb in terms of laminate thickness where internal frames become redundant? Frankly I'd rather cover her in 3 sheets of 1/8" or 1/4" marine ply and a coat of fiberglass than try and replace 3600 rusty, clenched nails from her planks.

    And encapsulating each plank is also beyond what I'm willing to do.
     
  4. gonzo
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    gonzo Senior Member

    You said it "1) lousy repairs never last but come up again and again and again...
    2) Old wood, clapped out wood, is very unstable. You finish it nice, and it cracks. You repair it, it cracks." There is no way around it. You could cold mold over and fiberglass, but then you should also do the deck it doesn't break at the sheer. Gerr's book has formulas for thick fiberglass on the outside only of the hull. It assumes epoxy coating the interior. You can't compare a carvel planked hull with a plywood Thunderbird. They are completely different structures.
     
  5. rattleandbang
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    rattleandbang Junior Member

    The deck is another issue. It's in good shape but needs new canvas anyway, so if I do the hull I'll do the deck as well.

    I know they are very different structures but the exterior materials would be the same, and I know what I'm getting into maintenance wise.

    I appreciate all the feedback. I'm starting to reconsider the process, although those 3600 rusty nails seems like a brutal job. Half of them have been clenched, and how to get out folded over nails short of drilling off each head and pounding them through sounds like the 3rd level of hell.

    I could just sister them with galvanized screws as recommended by a shipwright, but I don't like the rust bleeds. They have been covered with just some kind of caulk, so maybe if I cover them with thickened epoxy they'll stop bleeding through.

    Maybe pulling the planks with a bar will provide enough force to yank out the nails. I'll have to start at one end and see what I got.
     
  6. gonzo
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    gonzo Senior Member

    Nothing known to man stops the rust bleeding. If you have access to the inside, through-bolting is easier than many other methods. You can use a holesaw of the same diameter as the bolt to take out the nails.
     
  7. rattleandbang
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    rattleandbang Junior Member

    Smallest hole saw I've ever found is 5/8. That's an awful big hole in a 2" frame...
     
  8. hoytedow
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    hoytedow Carbon Based Life Form

  9. PAR
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    PAR Yacht Designer/Builder

    Grind off the clench heads and pull them through from the inside with a vicegrip.

    They do sell fastener removal hole saws, that will follow the shank of a fastener, but I don't have a good source. I made mine from pipe, cutting a few teeth into them and welding on a shank for the drill chuck.

    One problem trying to apply something over a carvel is no matter what it is, strips, diagonal plywood, veneers, etc., all will be dependent on the planking's attachment to the structure, so if it's not soundly attached, you're gluing or fastening to mash potatoes. The last time I did something like this we cut each existing plank length wise on a resaw machine (3" blade band saw), creating two planks from the single original. A cheater was used on the inner layer to move it up 1/2 a plank width and all the planks rehung, essentially in their same locations, after dressing and restoring holes. The result was a double planked boat, no caulked seams and the bilge was dry. This is a lot of work, but does change a carvel into a double planked build, without much material. Of course you'll need a resaw machine, which isn't an easy thing to find and the willingness to half each plank's thickness. Another option would be to remove the planking, mill off a specific thickness, say 1/2", so you can rehang it over 2 layers of 1/4" diagonally laid plywood. Both of these techniques don't add weight to the hull and effectively converts it into a different method.

    The real question you need to ask yourself is how much do you want to get out of this boat, in terms of service. This will help determine which avenue of pursuit to consider.
     
  10. Pericles
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    Pericles Senior Member

    Paul,

    At #32, you mentioned truck bed liner as a marine exterior coating. I've used Protectakote Standard & UVR for the interiors of old dinghies etc., but your suggestion led me to call the UK supplier to confirm whether Standard would last protecting decking support posts in water, which would let me jetty the decking out over the fish pool in the garden.

    http://www.protectakote.co.uk/protecta-kote-anti-slip-coating.html

    He was unable to reassure me, so I think I'll go with encapsulating them with WEST Epoxy. OTOH, whose truck bed liner do you recommend please?

    Thanks,

    Perry
     
  11. rattleandbang
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    rattleandbang Junior Member

    My understanding is if you build up adequate layers of ply, it doesn't matter the condition of frames and fasteners because you now have a very different hull that doesn't need them -they become simply a mold. What I haven't been able to find out is at what thickness of laminate is that reached in a 30-foot boat?
    It would seem that splitting the original planks and double planking, that the intent is to save weight over simply adding more layers, but if the result is a dry hull, is increased wood weight such a concern given the loss in weight of waterlogged wood?

    These planks have shrunk a lot. If I decide to keep her a carvel, how much can you reasonably expect the planks to expand (1" thick VG fir). When these things are originally built do they leave them with (caulked) gaps to allow swelling, or are they assembled with the planks tight to their neighbours? I have some gaps on the bottom with at least 1/2" with caulking falling out.
     
  12. rasorinc
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    rasorinc Senior Member

    Use a Hog bit just larger than the nail or screw head, drill all the way through and let dry then use
    compatible dowels with epoxy.
     
  13. gonzo
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    gonzo Senior Member

    Planks are fit tight on the inside and open on the outside to allow for caulking. Caulking is a trade that takes years to learn properly. You hit the irons with a mallet until the ring right. That is a job better contracted out.
     
  14. Pericles
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    Pericles Senior Member


  15. PAR
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    This isn't correct. Simply covering a carvel with plywood doesn't get you out of the need for a sound structure and plywood substrate (the original planking). You can use this technique to bridge bad spots, but if the planking is shot and the structure weakened, you can mold whatever you want over it and it doesn't change what you have - a new plywood (or whatever) hull shell) attached to a bunch of shot planking and weakened structure. It's like putting plywood over termite eaten house studs. It'll look okay for a bit, but the plywood is hanging on and is attached to damaged structure.

    This requires some math and you can probably use Geer's book "Elements of Boat Strength" to figure it out, though some understanding of how things are done is helpful with this book.

    There's much more to gain with this method than some weight, the boat becomes a double plank and she'll be inherently drier, longer. Maintenance costs go down and durability goes up, but admittedly, this is an extreme approach, usually reserved for classics attempting to retain as much of the original look and material as practical. The one I did it on was built be a master, after being drawn up by a master.

    Thee are several factors at play and a good bit of experience to know how much moisture content, before caulking, how hard to caulk at this content, amount of tolerable edge set, etc. There's no set of rules, just experience, though some very general swelling rates can be offered, these are quite rough and not enough to base a decision on. Basically, you want to caulk with relatively wet planking, so most will pre-swell the planking with a hose or sprinkler, checking moisture contant along the way. Once the gaps have closed up enough and the moisture content is in an acceptable range, you can start pounding in caulk. According to George Buehler, you can teach yourself to caulk a boat by starting at the sheer and working down, assuming by the time you get to the LWL, you'll be good enough to do a reasonable job. I've never seen a novice perform this feat, but who knows, maybe you'll be the first, though I usually start at the keel and work up. I've also never seen a novice re-gel coat the whole boat in his driveway and get a good job of it, nor anyone paint their car with automotive LPU and end up with a result, that would rival something you'd pay for, but maybe I'm just too critical.

    Again, you need to decide what you want from this boat. If it's just a few more seasons of general service, then 'glass the crap out of her below the LWL areas and call it done. Of course this is usual a death nail for a wooden hull, but hey a few more years is all you wanted. If you want more, you should consider the alternatives, that have you repair or replace the termite eaten studs, before putting some new vinyl siding on this old gal.
     
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