Harken furling has been my defacto choice for furling genoas and jibs, and generally they’re super easy to install. There are a few tips and tricks I’ve accumulated over the years that make it a bit easier to be efficient during the build, and there’s recently been a run on fixing DIY furlers that highlighted a few steps in the process that people seem to neglect. See below for some pics to help you through assembling your Harken furling unit.
Before you’ve cut foils or made a headstay, first look around the rig and see if the ends of the headstay are appropriate for the furler. In the above picture, there is no toggle at the bottom of the stay, and instead there is a highly alarming twisted single plate with an offset pin to raise the height of the furling drum. Link plates in general are a bad idea for furling, as they tend to twist, but this is a single plate which has somehow managed not to tear apart. Toggles are far, far cheaper than rigs!Above you can see a link plate which has started to twist due to torsion from furling and sailing with reefed sails. Eventually one plate will break, followed by the other.
When looking at existing gear, it’s important to not only check for things like toggles, but make sure they’re working properly. The above mast had a jaw/jaw toggle installed overlapped (not inside) the masthead toggle, which had led to cracks in the toggle. Replaced with a eye to jaw toggle, which seats properly between the plates on the masthead toggle.
When making the connections between foils, I like to use the box that came with the furler to hold the adhesive, tools and all the small parts (some of which are very small indeed!) This lets you work quickly, as you can just slide all the necessary bits along the headstay as you go. The box catches any small parts you might drop, and can be used to elevate the foils when assembling stubborn connections. The single biggest mistake I’ve seen in Harken furlers gone wrong is not using enough sealant in the joints. In the photo above you can see that I’ve used the syringe to apply enough 5200 until it comes out the fastener port. Harkens joints are designed to have 3 levels of connection; first the mechanical joint formed by the shape of the connector inside the foil, second the fastener holding the foil to the connector, and lastly the bond between all the parts formed by the sealant. It’s far, far better to have too much sealant, and to hit the furler with an acetone rag, than to have too little and have the below picture in your sailing season!
The furler in the above image was a DIY unit 1, which had 2 foils come apart while sailing reefed. Luckily the owner was able to get the sail down without much damage. When I went to trouble shoot, I found that the connector barely had any adhesive on it, and the fasteners had none. Apparently the install was done on a cold day, so the adhesive wasn’t making it very far into the joint. I’ve also watched a DIY install use only a tiny amount of adhesive in each screw hole, as the owner “wanted to save the tube of loctite for something else” I’m guessing that the “something else” turned out to be fixing the furler later in the season!
Harken MkIV’s are stupid-easy to put together, but one slightly tricky area is in getting the connector wedges seated properly. In the above photo you can see the wedge, which is slid into place along with the connector. To make sure it stays in it’s proper place, hold it down with your thumb until the connector slides into place. You can also see the giant glob of 5200 which is coming out of the foil. This is a good thing! I like to finish off the install by wiping down the foils after the furler is stowed on the mast. There is some variation in tolerances on Harken furling, so if you’re facing a stiff connector, I usually chill the connectors in a cooler, or heat the foils, to gain a little extra play in assembly.
Naturally, you’ve chosen an incredibly cold day to assemble the furler. The adhesive that seals the connector in place is an incredibly important part of the joints between furler foils. In cold weather, both 5200 and Loctite cure slowly, so to ensure the bond kicks off and that the adhesive flows properly around the joint, I always heat up the joint after assembly with a propane torch. It doesn’t take much heat, so just move the torch over the joint until the foil is barely hot to the touch. Too much torch and you can melt the plastic bushings or spacers inside the connector. If you’re using Loctite as in the above picture, I like to line up the connector in place, then hit it with the torch BEFORE installing the screw for the first connection. That way you can tug on the connector to see how much heat it takes to set the Loctite. Also in the above image; always keep the Loctite bottle upside down when it’s cold, as this makes it easier to apply. Alternatively you can keep it warm in a pocket, but the obvious risks apply!
When putting the foils together, I like to leave the plastic wrapping in place, pulling it away from each end. This protects the foils from damage to the anodizing caused by dragging the foils. When the furler is fully assembled and attached to the mast, now it’s time to remove the plastic packing. All you need is a knife, held upside down in the furler track. Instead of moving the knife and possibly scratching the anodizing, just pull the plastic to the knife instead, so the plastic unzips around the blade. If you”re tantalizing the furler mast up, I’ll actually leave the plastic on until the headstay is installed, then while aloft I’ll slide the plastic off onto a knife. This leaves the plastic in place until the last moment, protecting the foils while you’re hauling the furler aloft, and lets you feel a bit like Errol Flynn, which is a nice way to end a project.