Well, I have to agree with Kurt as well. When we first fitted the new sail on Footprints I used a new aluminium tube yard which should have done the job, but for 3 successive years bent in the middle, but I was able to flip it over so it straightened out, and then bent the other way. It finally developed a fatal 30 degree bend. I then dug my solid, heavy, original timber yard out of the wood pile at the back of the shed and refurbished it. It had some rot in it which I easily repaired with some good old epoxy and a few scrap pieces of timber. The yard does develop a little bit of a bend sometimes, but it always straightens out when the load comes off. Every now and then I talk about a carbon tube yard, but really there is no advantage in that, and with the 4:1 purchase on the halyard the apparent weight saving would not be that great.

The timber yard is built to PJR specs for a timber yard matched to the size of my sail.

When changing back to the timber yard I threw away the heavy metal yard sling and glassed a piece of plastic tube onto the underside of the yard as a location for the Spectra lashing for the halyard block. This works well and saved probably at least 5kg in weight.

I must confess, that my own conviction is that 'wood is good' and that 'good wood is better.'  I've never broken a yard, but have over 120,000 miles broken about 10 wooden battens.  They were easy to repair.  I've bent one alloy yard and two T6 battens.  They were impossible to repair.  The battens were prone to bending again after being - more or less - straightened.  If I have time, I shall make carefully-seasoned bamboo battens for SibLim.

Some 'Humble opinions about yards...'

A yard needs to be a beam in every direction. I don't think it should be strengthened (like a bridge girder) for lifting, if in the design it's weaker sideways, for the sake of lightness. If it was strong enough in all directions before, it didn't need that truss-style weldment on top. Just makes it heavier...

If a yard is lifted with a two-point bridle or sailcloth triangle, and the triangle is high rather than low and flat, that's all good for lifting too, but if it's also made lighter and thus weaker sideways, it's feeble against all the other ways the sea will try to bend it.

And if this bridle/fabric triangle is low and flat, the poor yard faces the same forces at sea as any yard would, with the complication of an induced compression load between the bridle points, accentuating the tendency to let some dynamic load bend it out of column.

Gusts and wild waves don't make the sail heavier to hold up.

Among the fine materials for yards: Timber, guided by traditional scantlings, is one that offers toughness and forgiveness, and a good record of not fatiguing in secret or breaking at wee scratches.

For halyard attachment: Lashings, with several wraps around the yard, and a flexible connection - innately forgiving and robust, cheap and replaceable. Not the only way, of course.

Finally, why a lightweight yard? - unless you have carbon masts and gossamer sails and a yard downhaul to bring it down, and you want a faster roll period. Or your boat takes water over the rail when you only step aboard.

Kurt