The anchor almost appeared at the same time as the ship. When you need to stop the boat, you will drag the big stones tied with rope, the baskets filled with stones or the sand bags to the bottom of the water to drag the boat. In 3000 BC, Chinese and Egyptian sailors used this anchor. Later, two wooden claws were tied to the lower part of the tough wood to make a "wood anchor". At that time, it was called "ingot", which made it obliquely grasp the soil and was very firm. The earliest iron anchor appeared in 600 BC and was an iron hook with only one claw.
There were at least 12 anchors on the small sea ships in the Middle Ages and the late 12th century, and there were as many as 24 iron anchors on the sea. At that time, the weight of the anchor was light, and the anchor and the anchor depended on manpower. The weight of the anchor has increased since the winch was installed on the ship's deck. In the 18th century, a new type of bow-shaped curved anchor arm was designed using high-quality iron anchors that are not easily broken. Around 1770, the iron anchor completely replaced the wooden anchor. In 1821, the British Hawkins developed a claw anchor with an anchor chain. Between 1872 and 1887, the British C. Martin, S. Baxter and W. Q. Byers have improved this anchor. In 1933, the British Taylor applied for the invention patent of the plow anchor, which has twice the hook grip force than the traditional anchor.
Modern anchors are made of cast iron or forged steel. There are mainly pole anchors, which are mostly used in small ships. When the rodless anchor is used, the two anchors are simultaneously inserted into the soil and are most widely used. The high-grip anchor is suitable for sandy or earthy water bottoms. There are also some special anchors such as mushroom anchors and umbrella anchors, which are often used for long-term anchoring and positioning.