Swing keel bolts
My opnion is if you suspect the bolts. Then you should check out the entire mount. Pull the boat out of the water, drop the keel, inspect all the components, inspect the trunk itself and then reassemble. I bought my 81 minus a swing keel. The previous owner lost it while sailing. (it is somewhere at the bottom of the long island sound). The axle rod had rotted away. I installed a new swing keel, new bolts, new axle. I also found areas in the trunk that had chipped away and were paper thin. I repaired those with West epoxy. I have extra axle material and bolts if you need. (all 316 stainless steel) the screw I used require an allen wrench. ( I feel I can get them tighter than the stock phillips head) My boat was on a trailer when I did the work. I had to remove an axle from the trailer but I was able to do the install it all by myself.