Round Turn and Two Half Hitches
The name helps you tie the knot (except it is around the pole twice)
Purpose: This knot is used to secure a line to a pole, post, or piling. It’s more secure than a clove hitch and won’t slip under load.
Why It’s Important: It’s great for tying up to a dock post or securing objects on the boat, providing a strong hold that is still relatively easy to untie. It can also be adjusted for length without completely undoing the knot.
Note that it is extremely similar to the Anchor hitch except that the first hitch does not go through behind the first round turn.
Click the image to see an animation (opens a page in a new tab. On an App this will require internet access)