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How to Unstep Your Sailboat's Keel-Stepped Mast

Updated: May 14

There's something extraordinary, symbolic, almost melancholy about unstepping a mast.

When sailing, a sailboat exudes an aura of strength, power, and harmony. If the image of a sailing boat out of the water can still evoke an air of beauty, like a monument to the glory of the times of expeditions and discoveries, I find that a sailboat without a mast is stripped bare.

It's an almost sad and melancholy image of its sailing days.

But this stage also means the start of a new beginning.

Here is the unstepping process step by step.


Unstepping the mast of a 51-foot sailboat is no mean feat, and requires detailed and meticulous preparation. No less than 700 kg and 24 meters of mast will have to be removed.

To carry out this maneuver, a crane is essential, and it must be large and powerful enough to lift and control this structure meticulously because a mistake can be fatal.

Le gréement est libéré

Unstepping the mast of a 51-footer

Before D-Day

Preparation is everything. As on land, so on sea, meticulous preparation will avoid mistakes and surprises.

  • Prepare the supports that will hold the mast once it is down. These must be fitted with foam to protect the mast. We used an old foam mattress surrounded by old yoga mats.

  • All electrical cables running through the mast should be disconnected and released. Mast lights, VHF antenna, radar, and hydraulic hoses for the boom vang

  • Climb to the top of the mast to disconnect any equipment such as windvanes, anemometers, etc.

  • Measure the length of the shrouds by measuring the distance between the turnbuckles on your shrouds.

  • In the case of a keel-stepped mast, make sure you understand how the deck-mast joint is made, in case it is missing.


It's the big day, the tension is at its highest, everyone is there and it's time to stay calm and communicate clearly with your team and the crane operator.

  • When dismasting a large yacht, it's important to have a large enough team, but not too large. The golden number is 4, or 5 with one person there for support. Any more and we'll be stepping on each other's toes, making communication more difficult, and any less and we'll run out of hands.

  • The strap is installed below the second spreader bar. This can be done either by climbing the mast with a halyard, or with a crane.

  • The webbing is fitted with a retainer attached to the mast step. This restraint prevents the strap from climbing up and coming into contact with the spreaders when the mast is raised.

  • The crane grabs the strap and is ready to lift.

  • The backstay is removed, along with the forestay or stays if there are several. When unscrewing the turnbuckles, avoid using a screwdriver, preferring flat spanners.

  • If the forestay is fitted with a winder, one member of the team will be dedicated solely to checking it. His job is to make sure it doesn't get in the way of the maneuver, get damaged, or damage other components.

  • This is the moment to apply a little vertical tension upwards with the crane. This will prevent the mast from coming to rest on the deck as soon as the shrouds are completely free.

  • The shrouds and cap shrouds are released and attached to the mast foot with the stays and backstay using a rope.

  • Two long ropes are struck to the mast foot so that it can be controlled once it is in the air.

  • Now it's time to raise: the roles of the team members:

  • 1 person below deck will guide the mast from inside the boat

  • 1 person on deck will hold on to the mast step to control its ascent

  • 1 person controls the genoa furler

  • 1 person (often the skipper) directs the procedure with an overall view and communicates with the various crew members.

  • In our case, the deck-mast joint was made of Spartite, and the lubrication that was supposed to help when unstepping was dry. We then had to drill the Spartite all around the mast.

  • Once the mast was dislodged and in the air, we had to control it using the ropes installed beforehand and then guide it toward the supports already installed.

That's all there is to it. You have to stay calm at all times and be prepared for the unexpected.

Here's how our dismasting went.

After a 45-minute drive, we arrived at the boatyard at 9.30 am, and after talking to the boatyard team we knew where we were going to be able to put the mast, so we set about the task of installing 4 wooden supports on which we would place the mast.

We want to put it high enough so that it doesn't get caught in the snow and frost, so we're installing supports about 1 meter to 7 meters high. At the top, to protect the mast and the mainsail track, we're installing a sort of homemade cushion made from 20 cm thick foam rolled up in a piece of old yoga mat we've salvaged, which will hold everything together.

On installe la sangle avec la nacelle

Installing the strap with the basket

It's 1 pm and the moment of truth begins. The first step is to install the strap. To prevent it from sliding down the mast and coming into contact with the spreader, we installed a retaining line which we hooked to the mast foot. The strap is then attached to the crane and it's time to free the mast.

The junction between the deck and the mast is made with Spartite, a rigid polymer, but which offers a degree of flexibility to absorb the shocks and vibrations of the rig.

In principle, the fact that Vaseline was installed between the Spartite and the deck during the previous dismasting in 2017 should have ensured that the whole thing would slide as soon as a reasonable amount of tension was applied by the crane. But nothing moves.

Absolutely nothing, not an inch.

Fortunately, we had prepared for this eventuality and set about perforating this Spartite all the way around. We tried several times to raise the mast without success and started drilling again, until at around 4.15 pm the whole thing snapped and the mast rose a meter and a half.

L'équipe s'attelle à la tâche!

The team gets on with the job!

The mast is now 1 meter above the deck and it's time to guide it gently into its new extended position.

We had installed several ropes at its base to be able to control it and after a great deal of teamwork and communication, at 4.45 pm the mast was finally laid down on its supports while the team recovered from its intense emotions!

The whole operation took exactly 3hrs 45mins, as darkness set in during the maneuver and the temperature didn't rise above -10°C. The wind was gentle and even though it seemed to be strengthening at one point, it quickly settled down again.

Managing a 700kg mast is no mean feat and the stakes are no small matter, either for your own boat or for the neighbors, who always seem to be too close. But in the end, it was all done, in the best possible way.

Venus à côté de son mât

Venus next to her mast

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