What is the Square knot used for in the US Navy?

The Square knot, also known as the reef knot, is commonly used in the US Navy for joining two lengths of rope of similar diameter. Its primary applications include securing packages, tying down sails, and general utility purposes where a reliable, non-slipping knot is required. The Square knot is easy to tie and untie, making it practical for quick adjustments on deck. However, it is not recommended for critical situations where safety is paramount, as it can come undone under certain loads.