Purpleheart keel?

[Kyle]

Hi,

New to the forum. I am restoring an Elco 27' sport cruiser. The keel needs to be replaced and someone had suggested using purpleheart instead of a white oak timber. I was just quoted $1600.00 for a 26' 12/4 x14" oak board. Needless to say that is about twice as much as I had budgeted.
Any suggestions would be appreciated. Thanks

[Not A Guest]

Glue it up from smaller pieces.

[PAR]

If you can live with a non original construction method, a laminated keel is a better way to go. The cost will be about the same, but you'll think you'll be saving because it's built of smaller pieces. There's more labor in keels of this construction, so whatever the savings from the solid timber version will be eaten by the additional labor to laminate a keel. The laminated keel will be stronger, slightly heavier and much more stable.

If this is an investment boat (you plan to sell her one day) you should stick with the techniques, materials and methods used in her construction, or the resale value will go down.

[mmd]

Kyle, purpleheart is about the same weight as white oak and is slightly stiffer and harder than oak. It is slightly stronger in shear and compression, but about equal in tension. Rot resistance is about the same (good) as well. It would make a good keel timber, with a couple of "buts" - I find it a bit suprising that a good, clear purpleheart timber is less expensive than white oak. In my area purpleheart is significantly more expensive. The second "but" is that purpleheart has a grit in the wood fibres that makes it pretty rough on tools - you will spend a lot of time re-sharpening edge tools.

Another possible species for your keel is Angelique.

(Sources - Forest Products Laboratory. 1999. "Wood handbook--Wood as an engineering material." )

[Kyle]

Originally Posted by PAR

If you can live with a non original construction method, a laminated keel is a better way to go. The cost will be about the same, but you'll think you'll be saving because it's built of smaller pieces. There's more labor in keels of this construction, so whatever the savings from the solid timber version will be eaten by the additional labor to laminate a keel. The laminated keel will be stronger, slightly heavier and much more stable.

If this is an investment boat (you plan to sell her one day) you should stick with the techniques, materials and methods used in her construction, or the resale value will go down.

I would really like to know more about laminating keels. I have nothing but time since I am the one doing the labor.

[PAR]

Laminated structures are a "bread and butter" approach to building whatever. Quite literally, it is a wood sandwich of as many layers of lumber it takes to get the desired thickness.

In keel construction, it's getting hard and costly to use large dimensioned timbers for use in the dead wood assembly, so 1 by stock is commonly bent over a form in the shape of the keel and the layers are glued together. Less common is the stacking of glued lumber in straight sections and then cutting it up as if you were using solid timbers.

Laminating can afford complex structures, much stronger then whacking away at a big chunk of oak. You can orientate the grain the way you want for added strength as well, not possible with solid timber. It takes more time to build a keel this way, without a great deal of setup and planning, assembly line fashion, but a lot of folks think this is the way to go. In fact, some designs are a great big set of laminations, resulting in a boat from little bits of gooed up wood.

The biggest mistakes I see with laminating are insufficient setup and lumber thickness being to great for the glues to work properly. Most boat building books on the market currently cover the subject. Log onto the West System web site and have a look at how it's done, then buy their boat construction book and get their info pack on their products and techniques. They'll be a real eye opener.

[MacGyver]

White Oak is generally much cheaper than Purple heart or Jabota, unless you are in Europe? Oak is primo-priced there!
Have you considered laminating Jabota? Very hard wood and heavy (good keel wood if price is not as much an issue)
Full width Strips of 1/4in thick should be great.
TIME consuming, although you will have the woodkeel to be reckoned with!

[Kyle]

The problem with the exotics or white oak in substantial lengths is that I am located in Tulsa, Ok. With 1/4" strips what kind of chemical goo are you using to lay them up with?

[Ed Harrow]

Angelique will do the job, and it is, I think, a little easier to work than is purpleheart. Brad Ives, of Deepwater Ventures in Vinyard Haven, Martha's Vinyard, MA is a good source.

It is tough stuff, beating high-speed steel planer knives to death in only a few moments. It also tends to check, ring shank, etc, etc. It's important to keep it well supplied with "secret sauce" (~66 - 75% raw linseed oil, the remainder turpentine, applied HOT. Use a double boiler OUTSIDE!!) There is still, for you, the transportation issue...

Good luck!

[Not A Guest]

Kyle ---

There are several small mills in the area. One in Coweta on highway 51. I am sure that they can provide you with white oak of that size for less money.

The best option might be to laminate.