I read here about others who have caulked the forestay tang, which is a challenge, because it goes through the hull right between the two anchor shank channels, in a v-shaped recess. I tried their idea of using a soda straw on the end of the caulk tube to get down in the spaces beside the tang, but it was just a big mess.
I also had a 1/4" gap right in front of the forestay tang! No wonder it was leaking.
Looking for something to plug this hole, I discovered that Lowe's sells something called "backer rod," which is insulation foam in a 1/2" diameter rod shape. Reading the package, it says it is for filling large gaps prior to caulking. Hmm. That's exactly what I had around the forestay tang, a large gap, between the two anchor shank channels and the forestay! So, I cut some strips of the backer rod, and shoved them down between the anchor shank channels and the sides of the tang, until they came to about 1/4" from the top of the channel sides. I also cut some strips and stacked them in front of the tang. Then I covered the whole works with clear West Marine silicone caulk. After it dried, I put another coat of silicone over the backer rod stacked in front of the tang, and put a small piece of clear plastic in front to keep the silicone from sagging out before it dried.
Now the tang emerges from a very flexible but solidly caulked "V" that comes up to the top of the sides of the two anchor shank channels, and extends about 3/4" in front of the tang. I don't think this will be leaking again! And if it does, it will be a snap to re-caulk.