I have a ''74 as well.
Yes, counter-clockwise to lower the keel. When you release the catch, keep you hand on the handle (if it gets away from you, you won''t damage the keel, but you could break a finger when that handle is accelerated by 500lbs. of iron! (And it helps to keep the windings straight on the pulley).
It will go slack when it''s down. Then set the catch, give it one revolution to snug the cable, and you''re done.
When approaching the ramp/trailer, ALWAYS remember to come in with the keel raised. Do it first thing, before starting for the ramp from your slip/mooring, or if you''re daysailing off the trailer, as soon as you start up your engine in the marina after dousing sail. You don''t need it once the boat is being powered by motor unless you''re battling a mean headwind. There''s always someone doing something stupid at the ramp. Let it be someone else.
Yes, pulling hard once you feel the keel against the hull is not only unneccessary, but will damage your boat. As you crank it up, the tension will increase, because for 2/3 of the way you''re basically pulling 500lbs. of iron straight up. But when it nests under the hull, the difference will be quite obvious. When it stops, you stop.
If your boat "humms" while sailing, it means the cable is vibrating like a guitar string. Play with loosening the crank a bit and the noise will (hopefully) disappear. It won''t damage anything. It''s just a nuisance.
One more note: there is a handle under the forward dinette seat whose purpose is to lock the keel once it is down (it''s basically a big set screw). Before dropping the keel, make sure this handle is backed-out, then snug it down lightly after the keel is down. If it''s a ''74 like mine, it''s probably not effective anymore, because someone has raised and lowered the keel enough times with this set screw cranked in that it''s left a gouge in one side of the keel. I''ve just backed it out and have left it that way. The weight of the keel is plenty to keep it down, and if I run over a sandbar, the keel will now be able to lift and drag right over the top of it. I never give it a thought anymore, and she sails just fine.
Hope this was helpful.