Hey Tom, The answer to your question is yes, that horrific split was caused by steel ballast that somehow got wet, rusted, swelled, and expanded so much that it fractured out not only the outside skin of the keel, but it also completely destroyed the centerboard trunk (the pocket that the keel centerboard retracts up into). This was an extreme case. It was so bad that the entire keel was cut completely off the boat, a new one laid up in the original M17 mold, and then it was bonded back into place, completely replacing the keel, ballast, and centerboard trunk. This time lead ballast was used rather than steel to prevent any chance of it happening again. The job was above my pay grade so I took it to Bob at Montgomery Boats and he did the repair for me. Sean M23 "Dauntless" M17 #44 Paradox "Scout"