How to Build a Box Anchor

Boats need to stay in place when anchored, especially at night, when strong winds can be present. Box anchors are reliable, offshore-type anchors that use teeth set into a metal square frame to attach themselves to the ocean floor. All anchors use some form of spikes, hooks or teeth to dig themselves into the ground, but box anchors hold strong even if the wind direction changes, as the anchor simply flips over and holds with the teeth on the other side of the steel box-frame.

Things You'll Need

  • Welder
  • Angle Iron
  • Metal Saw
  • Chalk
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Instructions

    • 1

      Create a design for your box anchor. Use 1/8-inch steel with a 12 by 12-inch frame for a small boat and 3/4-inch steel for a larger vessel. Cut the steel angle iron to size so that you can create a box frame of the desired size. Cut eight teeth for the anchor. These should be triangular in shape, almost like a shark-tooth, and be about 6 to 8 inches long.

    • 2

      Weld the box together one corner at a time until the square is complete. Attach an eye bolt in the middle, at the front of the square. This will be where the anchor rope will be attached.

    • 3

      Mark the frame where you attach the teeth. Place them so that there are four on top and four on the bottom. Begin to weld them onto the frame on one side, welding them side by side at a 45-degree angle on the front and back piece of the square instead of on the sides. They should be angled toward the front, where the eye bolt is.

    • 4

      Flip the anchor and attach the remaining 4 teeth to the other side, facing in the same direction. This will ensure that the anchor grabs, even if the boat goes overhead and flips it. Whichever way it is turned, the rope will pull the teeth into the ground to secure it.

    • 5

      Attach a rope to the anchor and test it in the water. If it needs to be larger, make sure you don't make it so heavy that you cannot lift it out of the water.