Hi guys,
Starting to collect supplies for my build.
Any pros and cons you would like to share with a new guy regarding choice of lumber for a keel?
I have available to me kiln-dried white oak that I was thinking for the keel.
Mainly for the rot resistance and also for a little more weight down low.
Any thoughts on the subject?
Thanks,
Dave George.
Btw, I hope everyone has a Happy New Year. Margaret and I are in Muskegon, MI for the holiday weekend.
White Oak can be a good choice for your keel.
I would still build it up in layers as per the plan and if you have a choice in the wood, try to find quartersawn lumber with as straight a grain as possible. You will find that it will have less of a tendency to cup or twist which will pull the layers apart and allow moisture to collect and eventually develop into rot.
Although I've seen quite a few keels laminated from short lengths as a glue lam beam might be. Strong as anything and won't warp. Care is taken to alternate the laminations so that the grains run in differing directions and of course joints don't line up with one another. Just a little more difficult to cut to the final curves and dimensions.
Many builders have joined narrower boards and varying lengths of boards to build up the layers to make up the overall lengths needed of 1X 12 stock. Biscuit joiners make relatively quick work of this if the joints are flush. Just stagger them so that the joints don't lay over one another. Then cut them per the plans and charge right on with it.
Quote:White Oak can be a good choice for your keel.
I would still plan to build it up in layers as per the stock plans and if you have a choice in the wood, try to find quartersawn lumber with as straight a grain as possible.
Thanks Barry,
I still planned on making it up out of "1 by" stock. I will have to inquire about quarter-sawing and see if it will be cost prohibitive or not.
Dave G.
Quote:Although I've seen quite a few keels laminated from short lengths as a glue lam beam might be. Strong as anything and won't warp. Care is taken to alternate the laminations so that the grains run in differing directions and of course joints don't line up with one another. Just a little more difficult to cut to the final curves and dimensions.
Am I understanding this correctly? Are people stacking up 2-1/4 inch wide boards on top of each other to laminate their keels? The lamination would be perpendicular to the way it is done in the plans? Thx in advance. Andy
I built my keel from white oak. I was able to get 1x8's 12' lengths and spliced them together and laminated them. It wasn't hard at all. With narrower widths I would probably biscuit join them to make the wider planks. It really makes for a nice keel for the reasons you stated. It is strong and the extra weight is a good thing. Goog luck to you in your build.
Andrew,
Yes, you understand correctly. Keels were laid up this way for hundreds of years on boats. On smaller boats with their tighter curves it wasn't always a really good way to go if you were trying to make it a curved section. But there isn't any reason you couldn't laminate 2 1/4" wide white oak boards flat side to flat side and then cut the resulting glue laminated keel to the right profile with a band saw. I would drill oversized through holes vertically at regular intervals to place threaded rod centered in the holes in epoxy to pull them tight and keep it solid. Alternate grain patterns so that they run counter to each other on the layers. Coat the threaded rod with vaseline first so that the adhesives don't stick to the rods. No worries about weeping around the rods and causing rot that way. And they will be stronger than the material by a huge margin.
With the threaded rods you can place flat plates on the outer surfaces and tighten them down to pull the assembly together tightly while the whole assembly cures. Not too tight if you are using epoxy, but I would be more inclined to use urea resin adhesives (Dap/Weldwood Plastic resin) as they don't suffer from squeeze out like epoxy does. Helps if you can run the layers thru a surface planer first to assure that they are all the same thickness. Also thru on edge so that you have squared off sides. Saves a lot of frustration that way.
Then just trim off the threaded rods after you are all done and counter sink the nuts and fender washers so that all is flush. Still wouldn't glass it however, you want to be able to see any seperation and take care of it before it can become damaged.
The laminate is vertical not horizontal, though horizontal laminates are common in other boat keels and a fine way to do things. A three layer sandwich of 1 by stock (3/4" nominal), one down the centerline and one on each side of this, make up the 2 1/4" thick deadwood assembly. Extra strength can be gained by scarffing the joints. Biscuits can ease assembly (keeping things aligned as you assemble the pieces), but offer no additional strength. Most just butt the joints and considering the minimal loading on this keel, it works out just fine. A side note would be a horizontal laminate is much stronger, but typically is bent over a jig or mold. The vertical laminate does away with this necessity and makes it faster and easier to build the deadwood.
When faced with the need for wide boards, I always rip them into smaller sizes and stack them on edge to get the width necessary. This eliminates many of the internal stresses in wide boards, which lead to checks, cracks and cupping. Most folks end up using flat sawn lumber, which is all they can find with a reasonable price. These work fine, but are prone to warp and cup. Glued and screwed inside a keel, these pieces can be partly contained, but some splitting, checking and cupping can still occur, which can let moisture inside to do it's nasty stuff. Ripping 8" boards down to 4" ones, then gluing these in place on top of each other will go a long way toward removing this problem. In fact, I never use a board wider then 4", unless the grain is particularly straight, tight and close to vertical. Yes, it's extra effort and more glue lines, but the insurance it provides is cheap compared to repairs. It also permits you to use lesser quality stuff, cutting around bad spots and concentrating on putting in the better part of each board, rather then just accepting the good with the bad in each.
Cool, thanks Paul.
Everyone has been very helpful on this board.
David George
Interesting. I would have thought that a horizontal laminate in a small boat would be a bit weak in the transition area above the knee where it rises to become the stem. Since the curve in a small boat is too tight to bend, the strenght there would rely on the glue joint. I guess with modern glues it wouldn't be an issue but I like the idea of sinking in threaded rod.
Threaded rod or any bolt, screw that has it's threads cross a glue line, will commute moisture across the glue line, by way of the treads. Water will follow the spiral of the treads, into the structure. The only time I've seen this thwarted is when epoxy bonding techniques are used to secure the fastener(s).
For some time (many decades) glues has far exceeded the strength of wood. Even yellow carpenter glue (milk based, but must be kept dry), which has been around for centuries, will rip up pieces of wood along a failed joint. The glue didn't fail, the lumber did.