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Thread: Splining

  1. #1
    Join Date
    Jun 2005
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    Hampton, VA, USA
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    Default Splining

    With Spring here, I'm going to start splining Favona soon. I know there are purists among us who are horrified at the thought, but it's either spline her or she dies. I have tried to sell her without success and either she dies on the hard or I spline & cold mould her. Splining can't be all bad, I think Stormy Weather is splined now and Curlew's been splined for several decades. Favona's 57 years old & I'm not prepared to do what would be required to make her tight & dry using traditional methods.

    Years ago, I was a purist too, but I watched the lovely Norwegian sloop of a close friend die when he refused to deviate from traditional methods & materials.

    So, for those of you who are more pragmatic that purist, what is the smart money saying at this time concerning splining? What wood? How wide? What's the down side of packing cleaned out seams with epoxy/wood flour peanut butter, other than cost? I guess she'd be hard to fair w/ alternating hard & soft materials. She's 32' long.

  2. #2
    Join Date
    Apr 1999
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    Hyannis, MA, USA
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    Default Re: Splining

    For the splines, some softish wood like cedar worked well on Granuaile. The planks were epoxied in and out. Today I'd go with CPES.

    Granuaile as not sheathed. If you do a good spiling job and have removed all bad wood first, you end up with a strong monocoque hull. If she's at all beamy, like fatter than 4:1 and a big sail area, the wracking strains might be more than the chain plates can easily distribute. In that case, wood sheathing like my friend did to his old Wianno Sr is surely called for. In Granuaile's case, it was not needed.

    I'd NOT pack the seams with epoxy. Firstly, it's much cheaper to use wood. Secondly, it's more consistent with the hull structure. An epoxy seam will, I think, just crack itself, crack planks, and/or crack frames as the rest of the wood swells and shrinks. Router out the seams to 3/16" or so wide and soft wood spline - a proven approach over the last forty years or so.

    I'm not really qualified to know whether your boat needs a sheathing over a splined hull or not but I can't even give bad and gratuitous advice without knowing . . . what sort of boat is she?

    G'luck

  3. #3
    Join Date
    Aug 2004
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    Portland, OR
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    474

    Default Re: Splining

    I suspect somebody's going to come along asking for more details about the hull's problems, so it might as well be me. What's going on that makes you think she needs splining?

    Also, I think the summary of Ian's advice is that generally putting anything in the seams that's less compressible than the existing planks will cause problems--hull planks getting a lot of compressive set, or straining the frames, or the planks splitting if the boat dries out. Therefore, cedar, especially very stable and soft cedar like northern white cedar, is probably the best material. But that's not from personal experience, so. . .

  4. #4
    Join Date
    Jun 2005
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    Hampton, VA, USA
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    Default Re: Splining

    Thanks for the quick reply gents. The boat I'm working on is Favona. I'm not sure if I own her or she owns me. She's a Robert Clark design, built at the Aeromarine yard in England, luanched in 1953. She won the Fastnet that year with her designer in the crew. She's 32'6" LOA, 8' beam, 24' LWL, 6' draft. African mahogany copper riveted to oak frames. In the style of a number of post-war British boats, she has wrought iron straps in lieu of wood floors. The keelbolts only come up thru the wood keel. Not surprisingly, with the now tired straps and poorly distributed keelbolt loads, she's leaked like a sieve for years when going to windward.

    All that to say that she is old & weak and the only way to renew her with traditional methods and materials would be to use her as a pattern to build a new hull. She's a magic boat &, while I've picked up a small plastic boat, I can't let her die on my watch. I've had her for almost 25 years.

  5. #5
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    Apr 1999
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    Default Re: Splining

    I don't think sheathing will improve the grip between keel and garboards. Sounds like new floors and keel bolts, maybe exterior strapping between keel and chainplates. Given that taking care of the structural issues, I think splining would really do the trick.

    Keep us in the loop. A very worthy project.

    G'luck

  6. #6
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    Aug 2004
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    Portland, OR
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    Default Re: Splining

    Hopefully someone who is more knowledgeable than me will come along soon, but here's what I wonder: if the floor timbers have gone funny and the garboard opens up going to windward, are the forces big enough to crack open a glued garboard seam? The glue's only going to be a little stronger than the cross-grain strength of the wood. Are there any professional boatbuilders around who could take a look in her belly?

    OK, now I see Ian's post, and it's really what I wanted to ask, but didn't have the guts.
    Last edited by Bill Mercer; 03-21-2011 at 07:06 PM. Reason: Saw Ian's post

  7. #7
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    Oct 2008
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    Walney, near Cumbria UK
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    Default Re: Splining

    There should be clips under the keel bolt nuts holding the floors down. Any sign of them? Do you have to replace the floors with iron, or is there room under the sole for timber crook floors with good long arms? That should sort the leaking garboards.
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
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  8. #8
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    Jun 2005
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    Default Re: Splining

    There are no floors and the keelbolts are cast in, so I'd planned to put in new keelbolts & floors with semi-ring frames, laminated across the top of the floors and up to the shear clamps, to better distribute keel generated forces.

  9. #9

    Default Re: Splining

    Wow, that is the first mention of another boat from the builder of my own. I have a 1954 Robert W Clark 22' sloop built with double planking (inner diagonal, outer fore and aft) of honduras mahogany. It too is copper riveted to small ribs (3/4"x5/8") and has been out of the water since 1972 sitting dry in a barn awaiting me as a new owner. My planking is both thin, with a layer of 1/4" and one of 3/8", and dry and in need of both replacement of some planks close the garboard and repairs of others.

    The main issue is the planks that are in good shape. Previous owners have put a sikaflex style goo in between the planks (tight seam, no cotton) and there are now uneven gaps in the dry planks ranging from 1/16" to 1/4" minus. I have been leaving the boat dry until I get her closer to launching since it has been that way for decades, but plan to soak it up for at least a month or two before launching. I know that my planks will swell, but the uneven gaps seem to say that the plank edges are crushed from the sikaflex. Plank widths are 4.5" max so when I plug my numbers into a wood shrinkage calculator the max value I can get with a 30% to 10% swing is 1/8".

    So could I spline a double planked hull? Again the inner diagonal planks would not be touched, just rout the outer planks uniformly to take cedar or mahogany splines, epoxied to one side. This does save both the precious honduras mahogany and the 3000+ copper rivets that would need to be cut and reinstalled to replace the outer layer of planks.

    I should just start a post for my boat, but I have put off working on her for a few months to build a woodshop in my barn. Now that that is done with a new bandsaw, jointer, tablesaw, workbenches, lighting, space, etc. I should be back to work soon. Thank you for spring!

    Matt

    P.S. I have been lurking here for a few years and would like to thank everyone for their time and input that has already helped me greatly.

  10. #10
    Join Date
    Oct 2009
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    Lexington, SC
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    Default Re: Splining

    I don't now anything about this but will be watching the thread with interest. How wide are the splines? What would you put over it? How thick?
    Chuck Thompson

    1955 18' Chris Craft Continental
    1950 30' Chris Craft Express
    1955 Concordia Yawl #26 (under restoration)

  11. #11
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    Apr 1999
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    Hyannis, MA, USA
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    Default Re: Splining

    I see no problem with spiling a double planked tight seam construction but I would do some study - it might well be the place to put epoxy on only one side or even neither. That I don't know. Might not be so testable since conventional spiling with epoxy all around (under as well, maybe, depending on whether the two skins are connected) would likely work quite well also.

  12. #12
    Join Date
    Jun 2003
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    Seabeck, WA
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    Default Re: Splining

    Keelbolts,

    Definitely soft cedar wedges. Either Western Red of Atlantic White.

    For a good bond with the epoxy, after conventional reefing I wouldn't hesitate to fire up the small, gasoline-powered power washer using a nozzle that will abrade wood to bring those plank board edges down to bare wood so as to maximize the epoxy bonding. If the power washer happens to knock a chunk off, you didn't want that chunk in there anyway.

    I'd set the wedges a bit proud, and fair them after the epoxy cured using a jack plane. Then perhaps microballoon fairing compound and longboard if I wanted smoother.

    It'll probably all hold up fine until the boat is again pulled for a long period of maintenance. If you can't keep it in the shade in a high-priced covered mooring then rotate it periodically.

  13. #13
    Join Date
    Nov 2000
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    jarvenpaa,finland
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    845

    Default Re: Splining

    I have been told and it makes sense that re framing before splineing is a must, as the planks are now tight there will be more pull on the frames and expect some frames to crack now, yes the softest wood possible.
    making metal frames that bolt to the keel and have straps that run up the sides of the bilge will distribut the load, ive seen it done on almost every six meter to make a very stiff boat.
    There's one rich man onboard and there's twentyfive poor men and they enjoy it more then the rich man does -Jim Kilroy when asked if yacht racing is a rich mans sport.

  14. #14
    Join Date
    Dec 2002
    Location
    New Zealand
    Posts
    129

    Default Re: Splining

    My boat was splined by the PO. He used WRC and epoxy, and in all seems to be a success.

    My only gripes are that he then sheathed the hull with what looks like 6oz glass and epoxy. This doesn't seem to have the mana to hold up to the movement of the deadwood and keel area. Every haul-out involves sanding out some cracks in the glass and priming the bare wood. I figure that with everything wet, and time on the hard costing money, I'm better reverting to traditional methods.

    The glass on the softwood planking seems to be sticking.

    I did have problems with a few of the hood-ends on the bow. When they were splined there were voids in the epoxy leading back from the stem. Water had entered and run back about 10" and caused rot in a few planks.

    Over-all I think it is a realistic option, but it needs to be done with care. And if you are going to glass afterwards, do it to a decent thickness or not at all.

    Jonny.

  15. #15

    Default Re: Splining

    Well, it is good to hear that at least one person thinks that you could spline a double planked hull. The two layers of planking on my boat had a layer of doped canvas between them that has long since turned to dusty rags (1954 remember) and are only attached together by the copper rivets through both layers of planking into the ribs (two rivets per rib, ribs 4" apart). The inner layer was attached to the ribs by small copper tacks then the outer layer laid over and riveted together.

    I would think in my case the splining would almost be just a case of renewing the plank edges by gluing to one edge only, but I run into the problem of not being able to cotton caulk the seam afterward. Since the canvas layer is long gone, there is nothing to stop the water but the tight seams. Also, how about spline shape? I have a layer of planking only 3/8" thick with solid wood behind it. It seems that I do not have much room for banging in a tapered spline. Has anyone put in straight sided splines before? Any problems getting them to fit or glue well against the plank edge?

    I am also doing many more major structural repairs including a new forefoot timber, new floors, keel repair, ballast repair, rudder, deadwood, etc. So I can fit in any new designs that are warranted.

    I want to save this old girl and I am willing to put a new layer of outer planking on her up to the waterline with new bedding/canvas and new rivets. But it sure would be nice not to have to redo those rivets. They are old by age, but only saw 15 years of service and still have lots of strength and toughness left in the metal.

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