Harken Furler Extrusion Repair

The top of my aluminum furler extrusion was slowly being worn away by the much harder steel forestay fittings.   Last season, the furler would occasionally jam if the halyard wa too tight.  I was (and am) not sure if the jamming was related to the wear on the extrusion, but when the mast was unstepped it was clear that the extrusion needed repair.

This photo is from another 33, same problem, but not nearly as advanced as mine was.

I called Harken, a few dealers, and posted online, looking for a length of extrusion and a plastic connector for this vintage unit, and came up  empty-handed.   This meant that I had to either replace the entire furler, or figure out how to repair.

Interestingly, it appears that in both Windstar and the a boat shown above, the furler had been installed without a length of connector in the end, to serve as a bushing.  The tech at harken told me that the only bearing-like support at the head of the extrusion was provided by the rubber end cap.  (Both approaches, I think, are wrong)  The instructions however, show a length of plastic connector servicing this function.   It may be that the fitting diameter did not permit a the installation of the connector in this application.   Anyway, 30 years later, the extrusion is badly damaged.


Turns out the extrusion could not be removed from the stay, not easily anyway, so, the problem was how to strengthen
and slightly extend the extrusion, in situ, without gluing it to the stay?  How also to reinforce the end of the extrusion, and create some sort of bushing that would prevent recurrence of the problem?  I decided to cast a glass-filled epoxy part in situ.

To start, I trimmed an inch of damaged metal off the extrusion.

One of the challenges in this approach is how to avoid gluing the furler to the stay, and to provide adequate clearance between the furler busing and the stay.  I decided to make a sleeve with a water soluble clearance sleeve covered by a release liner, and to build an epoxy glass sleeve over that.   Using only the first high tech materials you see the sleeve below.

Mylar tack tape (release liner) over cheap toilet paper, (water soluble clearance sleeve) wrapped fairly tight. 

 Next, wrapping with strips of fine glass cloth then saturating with epoxy.  (reinforced sleeve around stay)

Then wrapped in waxed paper to kick

I was able to remove the toilet paper at this stage, my concern about it getting stuck inside unwarranted.After that, there was a tapered glass tube floating over the stay.      The part was then sanded, then set into a mold, centred and dammed with plactiscene.  the mold was then filled with glass-strand filled epoxy resin.  Below, just out of the mold.

That raw part carefully sanded to fit the inner contours of the extrusion.

then coated with resin and tapped home.  I preheated the extrusion to expand it.   A tight fit.

Then, the top was built up with more glass-loaded resin, and a new cap was installed.   Unfortunately, the cap  had to be cut to get it over the stay, hence the visegrips.

And voila!   Wrapped with rigging tape.  Good for another 30 years!