I did this job several years ago to fix the c&c smile. I bought a torque multiplier on ebay for the purpose. The correct torque is 300 ft lb. that's a lot of torque and you'll either need a torque multiplier or a BIG torque wrench. you'll need a deep well 1-1/2" socket on an extension. You'll either need 3/4" drive socket, extension and torque wrench, or, as I did torque multiplier on 1/2" torque wrench with 3/4" components elsewhere. You can do it in the water as suggested above, but if you can do it on the hard you can do a really complete job-
Loosen the nuts with the keel well-blocked, clean out the hull- keel joint and recaulk, then working one nut at a time, remove a nut and washer, clean out undre the washer, checking visible portion of bolts for integrity, and fill/caulk under, then replace washer and nut, loosely torque. After all nuts have been done, torque all together in steps like you would a cylinder head.
Not as good as dropping the keel, but a lot less work, and as my boat was fresh water it's whole life, everything was still sound.