This spreader bar is used in conjunction with the spreader base casting to transfer the compression loads to the mast on the Catalina 34 and Catalina 36 with non furling rigs. Often times the spreader bar can become deformed if the boat is sailed without the spreader base castings in place.
Below, under "Technical Support" you will find a detailed drawing of both the spreader bar and mast installation.
New spreader bars do no have the holes drilled for the spreader clevis pins. The new spreader bar should be centered in the mast and the hole locations for the clevis pins marked by dry fitting the spreaders with the spreader base castings in place. Make sure there are no gaps between the spreader bases, the mast and the spreaders before marking. Remove the spreader bar and drill the holes and reassemble. Check to make sure that there are no gaps between the parts in the final assembly.
Caution! Customers report finding remnants of broken spreader bases on deck and not knowing what they were. I can easily envision a helpful crew hosing down the deck after a rousing sail. Small pieces of the spreader base could easily be washed overboard without anyone noticing. Inspecting the spreader bases and spreader bar should be on your list of items to check during every annual rig inspection.
It is critical the spreader bases and bar be in place. Without them, the compression load from the spreaders will be applied to just one point on the side of the mast rather than being distributed across the entire spreader base. Under the best of circumstances, accelerated wear will occur at this point. In the worst case scenario, high load at the point of contact could deform the side of the mast causing catastrophic failure.