One place to check
If you are looking for a new one, you might check with DwyerSpars - they sell several different sizes and sections of aluminum spars. I had the same thing happen on my boat several years ago - the result of overstressing the boom at that point the night before when raising the mast, some deterioration at the fasteners due to corrosion, and the fact that with a mid-boom sheeting set up, there is substantial leverage exerted on the boom by the clew slug against that mainsheet attachment point (on my boat a single bail). It was very fortunate that I had previously installed a solid vang, as a soft one would have allowed the boom to snap back in recoil when it broke.
