My SH14 split a sprit

[Frenchpete]

(I've been trying to get this picture in here but with no success, so I'll just put the link in)
http://gallery.bateau2.com/displayimage.php?pos=-13580

We had just taken the boat out of the water (the mast was still up and the brail line had the sprit and the sail gathered up to the mast) and I was creeping up the boat ramp, when we hear this big c-r-a-a-a-c-k when we got out to look, the top section of the sprit was hanging and swinging from the peak of the sail!

The good thing was no one was hurt. I always inspected the rigging before we sailed and I never saw anything suspect. And it's kind of amazing that it broke at this time (driving slowly up the boat ramp), considering we have been sailing all over the place for 3 summers now! And in some pretty stiff winds sometimes. I believe Someone was watching over us!

I have to admit that when I built the sprit, I did something ..er...different than what the plans called for. I built the mast out of 12 foot clear vertical grain Douglas Fir, but with the sprit, I used 8 foot lengths, laminating three layers together, staggering the joints, then cutting to size. Well, upon inspecting the damaged sprit, it appeared as though there was a very fine crack in one section (because epoxy had wicked it's way inside). In retrospect, given the way I pieced my sprit together, I believe I should have fiberglassed it. No kidding, right?

Anyway, I'm going to go aluminum with the next sprit, and I'm wondering could someone tell me how thick should the aluminum wall be between the O.D. and the I. D. ? Thanks.

Richard

[Laszlo]

Alternatively, since it's a clean break, it might be possible to just re-glue it and to put a layer of CF ($4.95/ft.) and a layer of glass ($4.00/ft.) on it. Jacques sells the stuff here:

http://boatbuildercentral.com/products.php?cat=2

It looks as if you just need a few feet of each and it's really easy to apply -it's just a tube which you pull over the core. Even if you end up covering the whole sprit, it might still be less costly than aluminum, especially if you have to get the aluminum shipped.

Good luck & glad no one was hurt,

Laszlo

[gk108]

If you are going to get involved in the process of pulling sock over a round form and coating it with resin, why not just make a whole new carbon fiber sprit?

[Charlie]

It looks like there is a butt joint that goes part way thru' the pole. If that is the case the strength of the sprit was compromised at that spot. Butt joints may work in the hull but not in long, thin, wooden spars.
Aluminum tubing comes in a wide variety of alloys, tempers, sizes and scheduals . If you buy it from a mast supplier like Dyer you will eliminate a lot of the guesswork.

[Frenchpete]

Laszlo thanks for the picture help.

Carbon fiber ....hmm...something to consider. I would probably have to do the whole sprit, since (as Charlie observed) it's a butt joint (in fact, one of several). Guess I'll think about this a bit.

Thanks guys for the input

Richard

[Charlie]

My D4 sprit is made from scrap redwood for lightness and has a joint going right thru' the fat section in the middle. But, it's a 7 degree scarf and is full 12" long.
Of course, it will never see the stresses your's would but, the same principles apply.

[TomW]

Richard, the cost of carbon fiber/fiberglass will probably be less than a new Marine grade aluminum spirit. Check your options. It looks like the butt joint failed either the glue was pushed out when you joined the pieces or did you coat the pieces before you joined them. Whichever the wood should have failed before the butt joint.

Tom

[Charlie]

I don't think a butt joint on any exterior spar laminination is sound practice. In fact, this is the first time I've ever heard of anyone doing it.
It's only supported on one side and the glue in the crack is trying to hold two small end-grain surfaces together. Once that joint experiences tension, like when the spar bends away from the butt joint, the butt is going to open up because the epoxy won't stretch. You may be able to get away with a butt in the middle lamination but, I wouldn't try it on any spar intended to control a sail over 60 sq. ft.