What is the best knot for securing a boat to a mooring?

A round turn and two half hitches is the best general-purpose knot for securing a mooring line directly to a suitable ring or post; use a bowline when you need a fixed loop. For regular use on a swinging mooring, a properly sized strop with a spliced eye and chafe protection, secured to a suitable cleat aboard, is a better long-term arrangement.

Check the attachment point

Attach to the buoy's designated load-bearing ring or supplied mooring strop. A small pickup buoy, its handle and its light retrieval rope may serve only to bring the main strop aboard.

Inspect the ring for rough edges, rust and worn sections. Check the rope where it passes through the ring, bow roller or fairlead. Chafe often matters more than the choice between two correctly tied knots. A sound bowline cannot save a rope sawing across sharp metal all night.

Keep fingers clear of rings, cleats and tightening loops. Take the load on another line before adjusting or releasing a loaded attachment.

Choose the right knot

• Round turn and two half hitches: use this when tying directly around a suitable ring or post. The round turn provides friction while you finish the hitch, helping you control the line as the boat pulls.
• Bowline: use this to make a fixed loop through an attachment point or over a suitable post. It usually comes apart readily after heavy loading, but needs slack to tie or untie.
• Cleat hitch: the usual way to secure the inboard end to a deck cleat. Take a full turn around the base, add figure-of-eight turns and finish with a correctly orientated locking hitch.

The bowline's familiarity does not make it the best knot for every mooring. Repeated slackening and movement can loosen a poorly dressed bowline, particularly in stiff or slippery rope. Avoid a clove hitch alone when leaving a boat unattended: changing loads can make it slip or work loose.

Tie and check the knot

For a round turn and two half hitches:

1. Pass the working end through the ring and around its metal section again to form a complete round turn. Allow room for both passes without trapping the rope against a sharp edge.
2. Bring the working end around the standing part and through its own loop to form the first half hitch.
3. Add a second half hitch in the same direction around the standing part.
4. Dress both hitches neatly and pull them snug. Leave a generous tail: a practical minimum is ten rope diameters, or about 160 mm for 16 mm rope.