Rubicon 3’s Rachael Sprot explains how to avoid losing the lines in the mast, whether you're replacing an old halyard for new or mousing the mast over winter

Halyards need taking out of the mast if you’re unstepping the mast or the line needs replacing. It is pretty straightforward, but there are a few steps to follow to make sure you don’t create more problems in the process. Replacing a failed halyard at sea is an entirely different matter, and we’re not covering that in this article. Halyards run up to the top of the mast and then back down inside. Sometimes they go down inside a channel, but usually they’re loose, often alongside cables for your lights and instruments.

Mousing line

It’s crucial they never get twisted, so it’s much safer to replace a halyard with a mousing line than it is to feed in a new halyard from scratch. It doesn’t matter too much what the mousing line is, as long as it’s strong and thin enough. It should be twice the length of your mast, plus enough to take it back to the cockpit if you’re leaving the mast up, or to tie back on itself if you’re lifting the mast out.

Pick the correct end from which to mouse the halyard. It’s best not to use the standing end that’s attached to the sails, as there are often fittings on this end. Start at the working cockpit end. You may even find that a flat loop has been spliced into the end of a braid-on-braid line to make this process easier.

Joining lines

Securely attaching the mousing line is key. If you’ve got heavy halyards and very narrow sheaves then sewing the lines together end-to-end is best. If you have lightweight halyards then tying the mousing line to the halyard tail with a rolling hitch, and then taping over it to cover any edges that could snag should be sufficient. Once tied, give the line a good pull to ensure everything is secure.

Work the line through

Flake out the mousing line in the cockpit so it can run freely, and secure the end so you don’t lose it. Pull through from the standing end, keeping the mousing line under control. If the line gets stuck, gently work the line back and forwards; sometimes the knot or join will need gentle encouragement to get through the sheave.

Make secure

With the halyard out, make one end of the mousing line secure to the base of the mast, and the other end either back to itself, or tied to a secure point in the cockpit. Finally, label each halyard as you go. It is easy to forget which is which and therefore make mistakes when re-rigging.


To re-mouse the halyards, flake out the halyard, attach the working end to the mousing line that comes from the masthead, and check they are secure, before pulling back through. Ensure you keep hold of the standing end so it doesn’t disappear to the top of the mast. You may need to manually work the line through the sheave at the bottom of the mast.

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With thanks to Bruce Jacobs and the experts at, the UK’s specialists in adventure sailing and training.