Glad you got the keel out. I think the curved piece of metal is a friction bar. I'd temporarily remove it and rebuild what remians of the keel hole with fiberglass reinforced epoxy. Then put the friction bar back in place.
Regarding the mast....
If you have a few inches of mast above your main when it is fully hoisted, an inexpensive way to get it working would be to cut off a few inches of the bottom of the mast... then to get the height back, by putting a block of equal length under the tabernackle... like in this diagram
Of course you will have to lower your gooseneck so the boom is at the right height.
If you don't have the height above the main to cut off a few inches of the mast, then try riveting an aluminum sleeve over the base of the mast (a splint) and drilling a new hole through the sleve for the tabernacle pin.