Why didn't my mast break

[Brion Toss]

Hi there,
Beautiful picture. I'm glad your mast is still up, and that you and your crew are, too. As for why the wire didn't break, let's start with the wire. I magnified the picture, and it appears that the core was far less damaged than the cover; is this so? If it was, then we can count on at least some strength there, up to about a third of the wire strength.
Next, even at 30 degrees heel, you wouldn't have been approaching the ultimate load possible on the wire, so there would be some reserve. And then there is the safety factor, which was bound to help to some extent; how much you had would depend on the load.
Finally, tune might have been a component; if the intermediates were tuned even a little slack, less load would be borne by them than the design would indicate.
Altogether though, and even assuming the most favorable combination of factors, it seems likely that you were an erg or so of righting moment away from a dismasting.
Fair leads,
Brion Toss