Broken Boom

This is the front of the boom.  It broke approx 75 miles from Tortola. The bar running slightly uphill from left to right was originally attached at the little nub of metal to the right of the wheel. The entire piece was welded to a sleeve that fit inside the boom and secured with rivets. You can see where the weld was on the bottom of the bar. It looks like it peeled away over time. The axle that the wheels turn on was bent. I never heard anything actually break (or maybe I should say that the sounds of things breaking have all been accounted for). We were in calm seas and I just noticed it hanging there. I had been using the preventer on reaches and since it attaches at the aft end of the boom, I wonder if I could have caused some forward pressure on that joint. The axle is secured in the middle but also went into indentations on both sides of the sleeve. It would've bent just as the piece pulled apart.  They re-welded it for me in Nanny Cay and reinforced all the welds.