Taking Apart Our Forestay

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Last Updated on May 24, 2020 by Amy

On our sail from Saint Helena to Brazil, we noticed something quite troubling. The set screws that hold our forestay together were backing out, and some were already completely missing. This was causing misalignment between the luff extensions and was damaging our sail.

A properly aligned luff extension:

Our misaligned one. You can see the sail tear:

Our forestay is one of the three parts of standing rigging holding our mast up. The forestay is the forward part, connecting the mast to the bow, and then we have two cap shrouds, one on either side. Standing rigging is essentially thick wire cables holding the mast up. If you think about it too hard – which this project made us do – it’s actually terrifying how this is all held together.

Like most cruising boats, our forestay doubles as the furler for our genoa, our main headsail.

Our forestay is a Profurl C430 reefing-furling system. At the Profurl website link, you can find a download of a PDF manual with an exploded view – if you want to follow along.

The visible part of the forestay, where the set screw is inserted, is called the luff extension. That set screw goes through the luff extrusion and into the bearing holder. The luff extrusion is lightweight aluminum and the bearing holder is also made of metal. With the set screws missing from the luff extension, the bearing holder had misaligned inside the forestay, and we had to take the entire thing apart for a wont of a few set screws.

In writing this process out, it sounds fairly quick. All boat projects are deceiving like that. In reality, it took us six days to do this project, even with next day service from the machine shop.

And, of course, we would have loved to hire a professional rigger in Recife to do this project for us. Alas, no riggers ply their trade in Recife, so we would have had to fly someone in. Better to just learn and do it ourselves.

The first step was to take down the genoa. Even this was a learning experience for us, as in our five years of cruising, we’d never had to take it down. First thing in the morning, when the winds were light, we unfurled the genoa. David was in the bosun’s chair at the top of the forestay, helping guide the sail down. I was at the helm, feeding the halyard out, and our two dock friends were helping us by pulling down the sail and flaking it on the trampoline to keep it tidy.

Here you can see the top of the forestay. The yellowish ring is the halyard swivel, which is connected to the head of the sail, and the dark blue line is the halyard, that runs down through the mast.

The genoa down and flaked on deck:

Removing the forestay is actually pretty simple – if you take the tension off the forestay. To do that, we did two things. We tightened down very hard on our screecher halyard, which was connected to the bowsprit, pulling the mast forward and taking tension off the forestay. Then, we loosened the cap shrouds. This can be done with two wrenches at the turnbuckle for the cap shrouds. The big trick is not to loosen your cap shrouds too much, because then they will disconnect and you will likely cause a rig failure (aka a MASSIVE problem).

We did not loosen our cap shrouds enough in taken the forestay off, and as a result we bent one of the brackets at the base of the forestay. It was impossible to get the forestay back on without loosening the cap shrouds further.

Once the forestay was de-tensioned, there are two locking pins to undo, one at the mast and one at the base.

David, up the mast, tied the genoa halyard to the top of the forestay to help him manage to drop the forestay down. Our dock mates were still here, helping us as David managed the top and I eased the halyard.

The forestay is much longer than our boat and very difficult to maneuver around. We laid it on the side deck, with either end hanging off the boat. Fortunately, Starry Horizons was at the dock and we could tie the top of the forestay to the ramps or prop it up.

Then, you have to disassemble the whole thing. Fortunately that is fairly straight forward and David was able to do it with the tools we keep on our sailboat. The furler comes apart to get it off the forestay and we worked our way down to the bare wire. The real trick that stumped us for a bit was how to get the bearing holder off. Turns out the insides are two half bearings which, with a rotation, come out from the bearing holder.

This is a picture of the bearing holder and two half bearings assembled:

Here you can see the bearing holder and the holes for the set screws. From left to right, holes 1 and 3 have been elongated, holes 2 and 4 are fine.

Here is the extrusion disassembled. The top right is the cable of the forestay. The top left is the luff extrusion. In David’s hand on the top are the two half bearings, and the bottom is the bearing holder.

Our friend Hans took us to a retired machinist who operated out of his garage. Next day service, and for incredibly cheap, he drilled out the holes to the next size up, tapped them, and made us replacement set screws. He also fixed our bent bracket.

Once our parts were back, it was down to putting everything back in the opposite order. We applied red thread locker to the set screws to prevent them from coming out. It might be overkill, but having our forestay fall apart would be a serious problem.

The hardest part was getting the forestay back on since we hadn’t loosened our cap shrouds enough. With the help of our friends, we got everything put back together and our headsail back up!

It was a terrifying project because a mistake could be catastrophic and bring our entire rigging down. But, when you want to cruise the world, these are the kinds of things you have to tackle.

We have a rigging inspection planned when we get up to Norfolk so our work can be double checked.