Manuel: If you have not already done so, you may want to visit the MSOG site, and look at how the centerboard is attached: http://www.msog.org/models/m17/m-17-cb.cfm If you still have a board, and it will not come down...you need to know that a problem on some of the older boats, with cast iron ballast...is the cast ballast iron rusts..and swells the CB trunk tight against the board....which may also be rusting...and for whatever reason, it will not drop down. Or it may also have some mud or other debris keeping it lodged up. I think that would be a better problem to have than it being gone. But to find out for sure...you may have to haul the boat of the water. If you have a trailer...it's easy to see into the trunk with it on the water. It's either there or it's not...and then you proceed accordingly. If it's gone...a welding shop can make a new one from plate steel. The pattern is available. Good Luck, Howard M17, #278 Audasea