Brutopõhisõlme

Brutopõhisõlme, also known as a reef knot or square knot, is a simple binding knot used to fasten two ropes together. It is formed by tying a left-over-right overhand knot and then a right-over-left overhand knot. The resulting knot is flat and secure when tied correctly with ropes of similar diameter and material.

The reef knot is commonly used in situations where a temporary and easily releasable join is needed. It is often employed in sailing for securing lines, in first aid for tying bandages, and in general utility purposes. Its primary advantage lies in its simplicity and the ease with which it can be tied and untied.

However, the reef knot is not suitable for critical applications where significant load is applied, especially if the ropes are of different types or sizes. Under heavy strain, it has a tendency to capsize or slip, making it unreliable. It can also be difficult to untie after being subjected to significant tension. For more secure rope-to-rope fastenings, knots like the sheet bend or the double fisherman's knot are generally preferred. The reef knot should not be confused with the granny knot, which is a similar-looking but much less secure knot.