Any boat in the charter fleet should be able to take a hard grounding at hull speed on the front of the keel. If you snorkel the boats in most anchorages you will see it happens all the time. The rudders are not as sturdy unless you find one with a skeg in front of it. A yacht aground pounding in the surf us a whole other matter. Once the boat fills with water the sloshing motion will tear the boat apart from the inside. Even if you are very dilegent and responsible. Any cruising boat should be able to more than survive surfing down a wave and slamming into a container just below the surface.