Before you drop the keel consider how Catalina
deals with this. They sell a set of 10" (for the C27) stainless lag screws (wood screw threads on one end and machine threads for a nut on the other) that you screw into the lead keel in new holes drilled next to the old bolts. The lags are dipped in epoxy before they're screwd into the lead keel. The screw threads hold very well indeed in the lead. I think the epoxy may be to help seal up any gaps and, in the case of a Catalina keel, to isolate bits of steel left from the recycled wheel weights they used for the lead. It's important to drill the right size hole for the lag. Too small and it won't screw in. Too big and it won't hold.There is no advantage to removing the keel. You can't put new bolts in the old holes anyway. See last paragraph for the "ultimate" fix.Catalina owner's have been using this fix for years. The "Catalina Smile" is very common. It's fair to say it's a well proven system.Before you get too worried, haul the boat, have it set on the hard with quite a bit of weight on the keel (so it's tight to the hull as you tighten the hull/keel joint), then back off the remaining nuts and inspect the bolts. Next, if they look and sound OK (hit them wih a small hammer or another bolt. If they ring, that's good.) tighten the nuts with big washers under them using a torque wrench. If Hunter doesn't have torque specs use Catalina specs for a similar size Catalina. If they take the torque with no twisting or breaking off, that's good but not proof that they're really OK.When I did this job on a Catalina 27 recently, only the front bolt seemed bad. I installed the whole kit of five bolts anyway. What the hell, you're there with all the tools and beer. Why stop after only one? (bolt, I mean) For folks where the torque on their sphincter is such that they won't trust the lag screws, you can still drill down into the keel, then drill holes across the keel to intersect the up and down holes so you can insert new nuts and washers on the bottom end of the new bolts. Or, for the ultimate fix, drill new holes all the way through the keel and put in full length bolts.