Here in Annapolis, I have a bulkhead slip in which I tie-up my 2520 XL with two lines. The marina has I-beams mounted on two pilings that correspond to my stern & midships cleats. Each I-beam has a car to which I tie the boat. As the tides rise & fall, the cars slide up & down on the I-beams. It's a pretty sweet system that minimizes wear & tear on the boat. Spring tides & flash floods are not a major concern for me.