Dang, that looks rough. Your board does not have the telltale 'ran aground' notch at the top of the board. I guess usually the top back side will have a crack if you ran the board into the ground. Maybe you, or a former owner, hit a ufo with it? Could have been just hard enough of a tap to put a crack in the leading edge, without doing the usual run-aground thing.
Mine was pretty bad after last year. Most likely the prior owners had run aground, and not treated the boat right over winter months, and things get bad after a while.
Here's a shot of mine in the spring when a Boat Wizard pulled the board. There was a horizontal split in the board right at the water line:
He ground away a ton of fiberglass to expose wet foam board (and the boat had been out of the water in a covered, heated garage about 6 months when he pulled the board!). He had to let this dry out a while so that he could start getting epoxy to actually stick to it when laying new fiberglass:
The end result is pretty great though. I'm guessing the centerboard is not quite faired to the original specifications, but it looks pretty darned good to me!
I did hunt for a second board for a while. Found a few very old, very dated listings, called a few, the folks on the other end laughing that they had sold their board X decades ago after scrapping the hull. I left an ad up on the classifieds section here. Figure it might be cool to buy and rehab a second board to keep around...spare parts amirite? But it's probably easier to find someone good with fiberglass and glue than to find another board.
One thing Jon (the guy who repaired my board, he's done a few 7.9 overhauls) told me was not to leave the board down if you keep the boat in the water all summer like I do. I guess the problem ends up being: any little crack in the glass lets water in, and freeze-thaw in the winter months quickly takes it toll.
I think you live down south so maybe don't have that latter problem quite as bad? But still seems like practical advice, and it's a good little workout at the end of a sail to crank the board up

.