bead and cove strips

Discussion in 'Boat Design' started by Dijkhuizen, Oct 4, 2007.

  1. Dijkhuizen
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    Dijkhuizen New Member

    Good morning I am looking for bead and cove strip to build a 9.5 mtr sailing yacht,would anybody know where I can find this in the Netherlands, could not find it on the internet.
    thanks
     
  2. Landlubber
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    Landlubber Senior Member

    It is usually made by the builder sorry mate. It is not hard to do, just get a 1/2hp router, and set it into a nice solid table say 1000 x 700. Go buy a pair of router bits and run the wood along a fence to suit. That is all we do here, but I guess you could pay a fella with a spindle moulder to do it for you, I see no point wasting money. You will use the table forever once you have one, they are just so useful.
     
  3. moTthediesel
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    moTthediesel Junior Member

    Better yet --

    With 2 routers and jigs to hold them (one under the table and one over) you can do both sides of the strip at the same time -- big time saver!

    moT
     
  4. Willallison
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    Willallison Senior Member

    Bead and cove is certainly available here in Oz - it usually adds about $10 per square metre to the price of the timber, so you have to weigh up whether you'd rather pay someone else to do it or spend the time to do it yourself...
     
  5. Landlubber
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    Landlubber Senior Member

    moTthediesel, you are just soooo fancy.
    We are trying to save the poor bugger some money, not waste it :)
     
  6. alan white
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    alan white Senior Member

    By the way, there's a way to make bead and cove strips without any machinary, noise, or even much effort.
    Anyone who's ever made treenails knows what I mean.
    Cedar, especially, is soft enough to make this an easy method. The nice thing is you can have anyone do it. It takes little skill.
    Make a heavy hardwood box that has a slot going through it the width and height of a strip section (say, 1/4" x 1"). Mortise the box to accomodate a chisel specially rounded to the desired radius, and mount the chisel in the box with a clamping screw that allows the chisel to gradually be adjusted up into the slot's (say 1/4" wide) bottom. Another chisel is ground to match the first chisel, and you can guess the rest of the story.
    Push in, pull through the whole pile of strips, walking pace, repeat, do other edge. Accurate, QUIET, cheap (Chinese chisels will do). You're really not taking off much material at all. The radius can be quite large, like one inch, which means removal of (who's the mathematition?) um, 1/32"?
    Okay, I've never done this. I admit it. But it would work, even if not exactly as described. I do hate the sound of routers.
    Alan
     
  7. Landlubber
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    Landlubber Senior Member

    Alan,

    With all respect mate, that is all very well, but it misses a very fundamental function of the cove and bead, they are round.
    Being round they adapt directly to changes in camber, still retaining 100% contact. Mouldings are designed to lay flat, yes they create a very good locking fit, but in the use of cove and bead mouldings, the purpose is usually for strip planking (I may be off track here but I think not), where the hull shape needs the planks to be intimate in contact, but allow curvature as well as the work is being done.

    I would expect to hear the sounds of the router (s) soon!
     
  8. alan white
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    alan white Senior Member

    No no no no... I KNOW all that. What I said was, the use of a router isn't necessary because the amount of wood being removed is miniscule if the radius is about an inch. So a die is used, a sharp-edged shape exactly the same as a router bit's curvature (two dies, two shapes), and the strips are pulled through by hand. This is an old technique, but perfectly sound. It allows those without the router or bit set to still make bead and cove strips.
    No need to scream through with 2 hp if only a tiny force is really needed. It's inelegant and wasteful. Not to mention loud enough to damage eardrums.
    My description was NOT about the shape produced, which would be identical to the routed shape. It was about how to achieve the same shape without a router or a shaper.
    Same as making a mast, where initial cuts go faster using a power plane, but fine cuts, the finish cuts, are made using (ideally) a spar plane or a bench plane.
    For those without routers or bits, or those who wish to listen to Bach while they work, try using the dies. I have all the bits myself, but I'm going to try the die idea next time I make bead and cove strips.

    A.
     
  9. Landlubber
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    Landlubber Senior Member

    OK Alan, I understand, and am sure the "sounds of silence" will be in our ears as we work, you really live up to the Maine conception I have in my mind.

    Wooden boat building is both a trade and an art, and i really do love both.

    I happen to be a working shipwright (in China at present), making boats in fibreglass, but still love to use the hand tools at home, where time is not so critical that I have to make money or starve.

    I am so used to having to use power tools (time) that I sometimes forget to listen to the tune of the hand plane, but i do feel for your thoughts.
     
  10. alan white
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    alan white Senior Member

    I'm all charged up to try out this thing. I've used every power tool there is, I think. A lotta guys have no router and the bead and cove stuff is too expensive or not available/handy. Maybe an efficient solution for many home builders of canoes, etc..

    Alan
     
  11. Omeron
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    Omeron Senior Member

    Now that we are on this subject, i would like to have your opinion on this;
    For a sailboat of roughly 11.5 m, do you think it is good idea to strip plank
    the hull with a soft wood (pine for example)which can be easily shaped as described earlier,
    and then epoxy veneered two or three layers of say mahogany, to finish it properly. After the hull is taken out of the mold, perhaps the inside can be veneered also with whatever is desired.
    Since the veneers will also add strength and thickness, the strips can be made thinner and hence easier to produce.
    Do you think the two different woods with epoxy in between create problems in terms of all of them working together?
     
  12. alan white
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    alan white Senior Member

    Normally a hull retains the strip planking as innermost layer rather than being cold molded inside, though it can be glassed inside for strength.
    There's no problem using dissimilar woods with different expansion rates because as long as the wood isn't too thick, once locked together with epoxy, the wood becomes like a ply in plywood, not sufficiently powerful on its own to move the rest of the layup, especially if the grain direction changes with every layer.

    A.
     
  13. Man Overboard
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    Man Overboard Tom Fugate

    A strip planked hull is essentially a cored hull using wood as the core material. Light stiff woods make the best core. In the U.S. we usually use Western Red Cedar, Sitka Spruce, etc; Down Under they use Kari. Pine would not be suitable for a boat that you intend to last a long time, as it is not very rot resistant. There is substantial evidence that over time water migrates into the core, rot resistant wood species should be used. Marine plywood laminates would certainly aid in keeping the migration of water particles out, as the glue in marine plywood is water proof to the point that they resist not only water migration, but also vapor pressure.
     
  14. moTthediesel
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    moTthediesel Junior Member

    I wouldn't preclude pine as a material for a strip planked boat. Eastern white pine was for years used to plank (and deck) many fine, long lasting boats in the northeast and mid-west US. Indeed, the strip planked Hampton boats of Maine were always planked with pine.

    While it is true that the second growth wood we have today is inferior to the old growth pine of 100 years ago, even today it is certainly no less rot resistant than sitka spruce, and a whole lot less expensive.

    In regard to water absorption, a strip plank hull well sealed inside and out with a continuous vapor barrier (cloth and epoxy outside and inside) should gain very little moisture content even after years of use. Where substantial amounts of water (enough to support rot) have entered the core, it is always either through unrepaired damage to the barriers or bad fastening practices. Regardless of what kind of wood the core is made from, if you have a high enough moisture content to support rot, you have serious problems :eek:

    Naval architect Lindsay Lord specified pine cores for the strip planked naval patrol boats he designed in lengths up to 86'. He said that those boats were both extremly light and had very long service lives.

    moT
     

  15. moTthediesel
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    moTthediesel Junior Member

    I think that's a great idea!

    Are you talking about mounting the shaped cutters at an angle (to act like plane blades) or at 90 deg. to act like scrapers? My first guess is that there would be less tear-out with the scraper mounting, but that it might need more frequent sharpening that way. I would guess that either way you would need to cut the knots out of the stock first.

    I'm no fan of the 20k rpm howl of routers either :p

    moT
     
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