| I think that your cast steel keel has rusted at the bolt hole and griped around the bolt. |
Slacken the nut or nuts on the pin bolt. If this does not free the keel remove the top covers and run release oil or rust remover down at the pin position. Try pushing the keel at the rear end of the box and then pull up on the tackle or the winch. If this does not work you will have to drive the pin out and file out the rust in the keel hole. I do not think you will have any lead in a RL 24 swing keel.
Do you have two alloy plates at the side of the keel box as the disimilar metals can cause a growth or corrosion on this area pin? If this is so there will be a white powder around the alloy plates.
The problem could be caused by a combination of three things. Steel corrosion, timber in the keel box swelling or electrolissis. I think the pin bolt is made from marine grade stainless steel