A jury rig is a temporary, makeshift arrangement built from whatever is aboard to replace something that has failed, most famously a mast that has gone over the side. By extension, any improvised repair on a boat – a rudder made from a spinnaker pole and a locker lid, a stay replaced with a halyard, a tiller lashed to a rudder stock – is a jury rig. The beginner needs to know that a jury rig is not meant to be pretty or fast, only to get the boat and crew safely to a harbour. The experienced sailor adds that the quality of a jury rig is decided long before the mast falls, by what tools and spare gear are aboard and by how well the crew knows the boat.
Where the Term Comes From
“Jury mast” appears in English seafaring by the early seventeenth century. Its origin is uncertain: the most likely root is the Old French ajurie, meaning help or relief, though sailors have long enjoyed the folk explanation that it is a “jury” rig because it is only fit for the day. Whatever its source, the word carries the right flavour: a stand-in that serves until proper repairs can be made.
Dealing with a Dismasting
The first minutes after a mast comes down are about safety, not sailing. Check the crew, then deal with the wreckage. A mast alongside in a seaway is a battering ram against the hull; either recover it on deck if it is small enough, or cut it away. This is where bolt croppers, a hacksaw with spare blades or a cordless angle grinder earn their place, along with a set of clevis pin punches so rigging can be freed at the chainplates rather than cut. If there is any chance of using the spar, save it and as much wire and rope as possible. Do not start the engine until you are certain nothing is trailing near the propeller.
Then build. The usual candidates for a jury mast are the boom, the spinnaker pole, or the surviving lower section of the mast. The stump of a mast that broke above the spreaders is the best start of all, since it is still stepped and stayed. A boom stepped in the mast collar or lashed to the stump, held up by halyards and spare line to the chainplates and the stemhead, will carry a surprising amount of sail. Guy it forward, aft and to both sides, and keep the loads modest; a jury rig fails where a lashing or a shackle is asked to do a job it was not made for.
Sails for a Jury Rig
This is where the sailmaker’s point of view helps. A storm jib set upside down, with its clew at the top of a short mast and its head at the tack, makes a decent loose-footed mainsail. A jib hoisted sideways with the luff along the deck and the foot up the jury mast becomes a squaresail-shaped sail for running. Small, heavy sails are easier to control than large light ones, and anything that can be reefed is valuable. Storm sails with their own attachment points, a trysail with a separate track and a storm jib that can be hanked to a rope or wire stay, are exactly the sails that go up quickly on an improvised spar. A reefed mainsail set on a stump with the boom removed and the foot lashed to the deck also works well on a fractional rig that lost only its top section. Avoid full-length battens where the spar cannot support them, and lash rather than hank if the fittings do not fit.
Sailcloth matters too. A woven polyester sail with big patches and a tough leech will stand the chafe and the odd flog of jury service; a light laminate racing sail is not the one to sacrifice, although in a real emergency any sail that gets the boat moving is the right one.
Frequently Asked Questions about Jury Rigs
Should I cut a fallen mast away or try to save it?
Save it if the sea is calm enough to get it on deck or lash it firmly alongside without damaging the hull; the spar and its wire are the best jury-rig material aboard. In a seaway, if it is holing the hull or you cannot control it, cut it away without hesitation.
What tools do I need to deal with a dismasting?
Heavy bolt croppers or a battery angle grinder to cut wire and rod, a hacksaw with spare blades, clevis pin punches and a hammer to free rigging at the chainplates, a sharp knife, and plenty of line and lashings. Keep them where they can be reached quickly, not under the bunks.
A jury rig is seamanship distilled: knowing your boat, carrying the right gear and staying calm enough to build something that works. Think about it in harbour, and if the day ever comes, you will already know where the bolt croppers are and which sail is going up first.