Anytime I am in a area where the boat can be backwinded or current and wind differ or it’s going to be calm at night I trap the ball. It makes for a quiet and peaceful night and will avoid problems with taller balls. The method I normally use is to take the Mooring pennant to one bow cleat. I then run a dock line through the steel ring on the ball and to the other bow cleat. As long as the lines are adjusted to less than the width between the hulls the ball cant bang on the hulls or get up under the bridge deck. Don’t pull the ball dead tight between the hulls. You can leave plenty of slack and be fine. I like to see about 45 degree angles on the lines to the ball. Strangely as much as I have complained about the height of the boatyballs it’s easier to do this with their balls because they are tall enough to reach down and run the dock line through the ring. Standard type balls require you to either hoist the ball up out of the water or use the dinghy. As mentioned a added benefit at a place like Cooper is reduced swing room. I see people all the time put two dock lines extended as far as possible through the pennant loop at Cooper. This extends the swinging arc substantially. In addition to the bridgedeck problem it can allow the Mooring line to get between the keels and props on a cat. The wind comes up in the morning and Houston we have a problem!
George