Much of the design of modern boat anchors concerns performance in different bottom conditions. The anchors need to be strong, but they no longer need to be huge lumps of cast iron. Some manufacturers quote weight, but just as many do not. In sand or mud, it’s more about how well the anchor holds. If there are lots of reeds or seagrass, the weight becomes more important. Some experts suggest that you simply buy the heaviest anchor that’s practical to fit on your boat. It’s not bad advice, but good design can compensate for low weight, whereas high weight is no substitute for the right shaped anchor on small and medium craft.