Roger,
You obviously don’t want to draw attention to the mended flaw by using stainless screws permanently to hold one flap onto the other once they've been glued together. However, a couple of wooden dowels, secured horizontally with epoxy into parts of the flaps that have sufficient depth to hold them, might make the mend a little more permanent. The protruding dowel ends can be cut and sanded flush and then stained the same colour as the surrounding wood.
It’s difficult to tell from the photo the position of the split - port foredeck? If it’s where you might damage the wood as you bring your anchor chain in over the side, you have a good excuse to add a stainless steel rubbing strip to “protect” the wood where the split is. Or if you don’t want to use metal, a sacrificial wooden strip, shaped and stained to blend in. It will need replacing every few years.
