The Quick Stop COB Procedure
There are several COB procedures, each with its advantages and disadvantages. On keelboats, there are more options than on dinghies, as you can incorporate a gybe into the procedure without too much worry.
As in many aspects of sailing, the best procedure can be hotly debated. As Seamus Venecko famously said, "Ask 10 skippers, and you'll get 11 opinions and a fist fight". Personally, I am not religious about this. I have my favorites, both for dinghy and for keelboat (different), and I can argue their merits. But as a dinghy Junior tester, I will pass someone who can get to a stop right next to the target consistently using a procedure I've never seen before. The results count more than the method.
I want to talk about a procedure that works on keelboats but not on dinghies, the Quick Stop. It was developed by the US Naval Academy some decades ago when they looked at the various procedures and didn't like any of them, so they invented a new one. What they didn't like was that in the all of the others, you tended to get too far from the COB, and so you might lose them in certain conditions (at night, in heavy seas, or both, exactly the kind conditions where it might happen). So they developed a procedure where you stay very close to the COB throughout the maneuver. This is the Quick Stop, and you'll see a number of descriptions online. I've experiemented with this on our boats (Commander and Merit) in various conditions with various sail plans, and this is what I think will work.
Basically, you tack around and leave the jib backed. Then you do a rough circle around the COB with the main sheeted in all the way, trying to get about 2 boat lengths away when you are going downwind abeam of the target. You gybe when you are clearly downwind of the target and round up hard (main is still sheeted in at this point). Then you blow the mainsheet and slow sail to the COB, which should be a boat length or so away.
Here is a diagram.