Longship
Longships for the most part used two different kinds of anchors. The most common was a natural wood yoke formed from a tree branch. The weight was supplied by a stone passing laterally through the U of the yoke. The top of the yoke was closed by either a length of hardwood or a curved iron head, which kept the stone in place. One side of the head stuck out so it could dig into mud or sand. In the Ladby ship burial in Denmark, a unique iron anchor has been found, resembling the modern fisherman's anchor but without the crossbar. The cross bar may have rusted away. This anchor—made of Norwegian iron—has a long iron chain to which the hemp warp was attached. This construction has several advantages when anchored in deep waters or in rough seas.
Anchor bend
While the knot can become jammed in some modern materials, it is usually easily untied after moderate loads; it can be made more resistant to jamming by taking an extra turn around the object--this will make for a 1-diameter longer span of the end to reach around the standing part to be tucked (although in a case of tying to a small shackle or link of a chain, this might not be possible). It is the accepted knot for attaching anchors (or more usually anchor chains) to warps. The knot is very similar to a round turn and two half hitches except that the first half hitch is passed under the turn. In many everyday uses, the finishing half-hitch need not be made; alternatively, one might seek surer security by tying off the end with a strangle knot to the standing part.