A heavy stone tied to a crude rope was the anchor used by the earliest boatmen, but it took a heap of muscle to handle stone anchors large enough to keep even a dugout canoe from straying. Today, the dead-weight anchor has been replaced by far more efficient and lighter types with a hooking action.
One major anchor manufacturer claims that if a lightweight anchor had been designed centuries ago, the entire history of the world might have been changed! This sounds like an extravagant statement, but it’s true that the Greeks, Romans, Spanish and English might all have handled their ships differently in exploration, trade and battle if they could have made their rigs stay still when they wished it.
The technique of island jumping and amphibious landings used during World War II was made possible only by the modern anchor. Our Navy was able to put and hold ships in any desired location.
The size of the anchor you need for your boat will depend on many factors: the type of bottom on which the anchor will be dropped; wind velocity; exposure of the mooring location; the hull form, size and weight; and the scope ( length of the anchor line in relation to water depth) . The riding anchor line, incidentally, is called the anchor rode by the salty set.
Since only the hull size, weight and form can be securely determined in advance, the following generalities should serve as a guide in selecting an anchor: