I hit Archangel Rocks(last summers Hylas 70 accident) with my centerboard down. My centerboard was not designed to be raised that way,....

Essentially, the linkage fetched up inside the bronze centerboard trunk, and lifted the trunk right off the keel. The leverage was so strong, it launched the centerboard trunk parts through the nearly 1" thick plywood and fiberglassed cabintop.

I redesigned the linkage after that, today we would have slithered over that rock, which is 4' below high water.

This illustration is one I did for an article in CW but it sort of shows how the linkage only works when pulled, not pushed. The night to come was an adventure.