Monday, September 21, 2009

Hood Seafurl 800 Bearing Replacement

rev. 7-1-2016

On a pleasant windless day at a dock 150 miles from home, I decided to partly lower our furling genoa so that I could put a few stitches and necessary patches on the sacrificial leech cover. A simple morning task to pass the time in a sailorly way. We were 10 days into a 2 1/2 week cruise around the Delmarva. I released the halyard tension, lowered the sail a few inches, and watched 48 ball bearings merrily dribble onto the trampoline, filter through the netting, and plop into the harbor.

The furler had been prone to catching for the past few days. It would roll fairly easily for a bit, then seize, and after a good tug, roll easily again. The bearings in this furler are half-and-half stainless and Torlon, and it seems the Torlon bearings had worn down to where the stainless bearings would ride up over them. Eventually, the wedging force pushed the lower circlip out of its groove and the lower race fell apart, unnoticed. My genoa is a little to long on the luff but still, it sets very well with no halyard tention; in fact, some wieght rests on the tack, just a little, and this held the upper race in position. When I went to re-hoist the sail the the foil was lifted by normal friction in the groove, the top half of the furler was lifted, and everything fell apart.

Although I could no longer furl the sail, I could still use the luff extrusion as a foil, so we lowered the large geona and planned on using the much smaller self-tacking jib for the 3-day trip home. The weather forecast called for strong winds on the nose the first day, followed by spinnaker reaching conditions for the next two days. That is how it worked out, so the loss of the furler was no great handicap.

Back at home, after considerable stress over the great cost of replacement unit, I set about disassembling the furler drive. It is a simple matter: bring the jib and spinnaker halyards forward and tension with winch; place a pad under the boom and release the topping lift - this relieves some tension from the forestay; remove the plastic set screw between the luff extrusion and the drive tube, remove the split aluminum castings, and while supporting the luff extrusion, gently lower until it rests on the turnbuckle - the luff extrusion will slide right through the drive unit; lift both the luff extrusion and the drive unit and place a vice-grip on the flats of the lower end of the forestay wire - this will support these parts and keep the forestay from turning when the turnbuckle is loosened; remove the cotter pins, and loosen and remove the turnbuckle - it was not necessary to loosen the shroud turnbuckles; remove the vise-grips and slide the furler drive off the forestay, while supporting the luff extrusion; replace the vise grips on the flats to hold the luff extrusion in place.

Replacing the bearings is quite simple. Each race (4 races) contains 48 x 9/64-inch 440C stainless balls, McMaster-Carr part number 9642K31. Parts are also available at Pompanette Co.. They are most easily installed by assembling the races first, and then inserting them from the bottom up, flipping the assembly over as needed. I used waterproof grease, but if you are using plastic balls and wish to assemble the mechanism without grease you will still need something sticky to hold the balls in place; tooth paste works and will rinse out. I have used it on other projects with Torlon balls. Be certain to tap the circlips securely into their grooves. Be careful to position the four
set screws into the matching holes in the drive tube. In my case I was not able to separate the stainless steel basket from the bearing tube and thus was not able to reinstall the furler line in the normal manner. However, a clove hitch around the spool with the stopper knot on a dead-end has proven secure. The heads of the set screws provide extra grip.

 Even fully furled, with the sheet around the sail twice, there should be a few turns on the drum.

 If you cannot a proper knot through the hole (sometimes the drum is stuck to the core due to corrosion) the line can be secured with a clove hitch. The set screw nubs are enough to make it secure.

In my case, since I elected to get rid of the failure-prone mix of Torlon and stainless, I am using grease. To reduce the intrusion of salt spray I fitted a large (~3"x 1/8-inch thick, fitting just inside the tack fitting) polyethylene washer to the top of the stack, just above the top circlip. That is really the only place water can enter. I drilled a small drain in the stainless basket. We will see.

Notice that I also added a plastic ring above the furler as a drip ring, deflecting rain that drips down the forestay. Does it help? Not sure, but they are still smooth after 4 years. In a few more years I will open it up and re-grease, but for the moment, it feels and sounds (no squeaks or vibration--just smooth) like there is still grease in there.

What I am actually doing in this photo (11/2015) is spraying water NikWax repellent treatment on the furler line. I sail all winter and this prevents the line from freezing, which can be a big problem.

Piece of cake. I imagine I will be doing this every 5 years or so, under considerably less mental stress.


7-1-2016 update. Still smooth as glass.


  1. Drew,
    I am trying to rebuild my Hood 800 furler. My unit had the 9/64 balls that were badly worn in both the drive and the Halyard swivel. Pompanette as well as my manual showed they are now using 1/4" balls alternating between Delrin and Stainless. I live in Cleveland so McMaster Carr was a short drive. My problem is that with the 1/4 balls the grooves on the swivel tube no longer are in the right place. I suspect that thinner Thrust washers might correct this, but cannot find the recommended thickness when making this upgrade. The Thrust washers are .25" thick. After reading your blog I am wondering if I should go back to the original size. Any suggestions? Gary - Hunter 33.5

  2. First, I bet they changed some other dimensions when they changed to 1/4" balls. I suspect they went to every-other to avoid the need for stainless.

    As posted, I used 9/64" SS balls 4 years ago and it is still smooth as glass. I packed it full with a VERY washout resistant grease (Green Grease by Omni Lubricants, available through Advance Autoparts and NAPA) and added a plastic disk at the top to reduce water flow (see above). So that is all I know.

    Spoiler alert. I am into the 3rd month of a grease wash-out study for Practical Sailor Magazine, testing everything from the most expensive winch grease to some very common products. And the first place product is Green Grease, even better than Lanicote and winch grease. So I'm pretty sure Green Grease is the right call for practically everything marine.

  3. Came across this while searching for parts... wondering if you can help? A plastic piece fell out of the bottom of my mid 90's hood furler while trying to replace a broken line, it's about the size of a hockey puck and I assume it's a spacer between the larger tube under the drum and the forestay. It has two opposing set screws and I can't find a similar part online?? Also I can't get the drum to drop, I'm assuming it's just a corrosion issue holding it up, but maybe you know more? My email is I can send photos.

    Cape May

  4. Came across this while searching for parts... wondering if you can help? A plastic piece fell out of the bottom of my mid 90's hood furler while trying to replace a broken line, it's about the size of a hockey puck and I assume it's a spacer between the larger tube under the drum and the forestay. It has two opposing set screws and I can't find a similar part online?? Also I can't get the drum to drop, I'm assuming it's just a corrosion issue holding it up, but maybe you know more? My email is I can send photos.

    Cape May

  5. Brian: I added two more photos that show the drum furled, and the clove hitch that holds the line. In this case, I had just replaced the line and did NOT remove the drum to dos so. I secured the line with a clove hitch, with only an undersized stopper knot, which can probably pull through the hole. The clove hitch is made secure by the bite of the set screws, the stopper knot, which cannot pull through the clove hitch, and the wraps over the clove hitch. To repeat, replacing the line does NOT require any disassembly, only knot tying ability.

    Yes, the drum jammed on the core for me too. I was able to replace the bearings without freeing it.

    I recall the keys to removing the assembly are the spit hockey puck (part 18 lets it drop) and the bushing (parts 1-3 free it from the foil). You will also need to clamp the foil in the up position with Visegrips, and provide other support for the mast (two halyards brought forward).

    1. Hey Drew, Did you remove the core from the new line? If so, how much did you remove?

      Thank you,

    2. Yes. About 20 feet, but you still want core in the jammer when fully furled. Mark that point and subtract about 5 feet (it will stretch without the core).

  6. I have a '97 Hood 800 SeaFurl on my 31' sloop that was occasionally jamming. I couldn't figure it out because the bearings on the drum and slide seemed to work fine with no noticeable friction. So I decided that perhaps my forestay tension should be checked. I disconnected the drum assembly from the bottom shackle and removed the tack sockets above it. This allowed me to slide the whole assembly up onto the extrusion. I discovered that the centering ring was missing. Thinking that was likely the problem, I figured I'd order one or make one but reassemble it until I could add the ring. I took a half turn on the forestay before attempting to lower the unit. However something was holding the assembly to the extrusion and I gave it a quick jerk down to free it. That's when the rivets broke holding the top bearings. They popped out and bounced off of my deck into 7' of water with a soft muddy bottom. No chance of finding them especially since they are non-magnetic. So now I need more parts. Also the screw stripped out of the forward tack socket so I figured I should just replace that too. So now I need parts but can't find them. I figure a new furler with a rigid tube extrusion (not CDI type) will cost me about $2K to be installed by the yard. I need to keep looking for parts.

  7. I have a brand new, in box Hood 800 SL if anyone is interested. I sold my boat last year before I could install it. I'd let it go for $600 or best. In Chicago. Call or text 847-942-0198.

  8. Hey Drew, This is great information! I have one question for you though. Did you remove the core from the new line?

    Summer Wind

    1. See above, about 20 feet. Taper the end of the core and lock stitch.

  9. Where can the flattened furling line be found? I am in Ontario Canada. Is the furling line only flat because the core has been removed?

    Keen Ice 27

  10. Yes, you simply remove the core:

    Lock the core with a knot. Pull the core out with a knitting needle just a few feet before it enters the jammer, when the sail is furled, and trim. Pull out an extra 6 inches, taper by removing a few strands at a time, and milk it back in. Then lock in place with about 10 stitches of whipping twine. Easy. I did this on my new boat (F-24) just a few weeks ago.

  11. Saw your blog post and used it as basis for fixing my furler (Thanks!) My furler turned out to have the mix of 1/4" ball bearings and smaller Torlon bearings. I assumed (Wrongly! My bad!) That the Torlon bearings were the 9/64" bearings you noted so I ordered like 200 of them to replace the Torlon ones...but when they arrived they were clearly smaller than the Torlon bearings (which I should have miked before ordering replacements in stainless!)

    Initially, the stainless steel outer cover was seized to the lower aluminum barrel. I used a torch and PB Blaster. I got it to move about a quarter inch, but then it was stuck even after several cycles of heating, blasting, and beating. Finally just took a vibrating tool and cut across the collet part of cover and that freed it. Was thinking as I was cutting that I can just re-tension collet with a SS pipe clamp later... But this is unnecessary as the cover is secured to barrel with three machine screws. With cover removed I could get access to knot holding rope to rope spool so did not have to clove hitch rope to spool. Note: The 4 Allen screws that secure the rope spool to the sail-foil shaft should align with the 4 threaded holes in the sail-foil shaft and when properly seated should be flush with the face of the spool.

    Rather than mike and reorder the Torlon bearings I just decided to re-use them (with grease this time). I removed bearings from each race cleaned them and put them into separate containers... But I made mistake of assuming each race had same number of bearings - they do not!

    I don't know how you removed that bottom keeper on the lower bearings that are up inside the lower aluminum barrel - but I solute you! I went from the top keeper - which I laboriously slid up out of its trench with a set of curved picks (Home Depot $6) and a screwdriver. I slid the keeper about 8" up the foil-shaft which gave enough room for full access to remove and clean all bearings while sliding top cover, bearing races, and rope spool up and down shaft.

    When I finally exposed lowest bearing ring it was pretty clear that it was seized to shaft.

    At this point I transfered locations of Allen screw holes in foil-shaft up the shaft with a sharpy pen to facilitate rope spool alignment with holes.

    Re-assembly was pretty straightforward. I went from bottom to top. I used AquaShield grease. I suspended the whole assembly upside-down with a rope through barrel holes because my grease wasn't viscous enough to hold the bearings in place without the help of gravity. Alternate placement of larger SS bearings with smaller Torlon bearings as you work around each race. The first bearing went fine, but the second bearing wouldn't take all the ball bearings in the box! I soldiered on with a couple of extra ball bearings in my hand... Turns out the topmost bearing takes two more of each bearing to fill the races so it worked out in the end! Whoooo! (Swipes forehead!)

    After I got the lower two races greased and filled with bearings, I positioned rope-spool into place, aligned the Allen screw holes in the spool with my sharpy-marks, and secured the Allen screws so their heads were flush with spool face. Then I flipped assembly upright so I could fill top two bearing races.

    In the end, I got it all assembled with grease and then (laboriously) slid the top keeper back down the foil-shaft and back into place.

    Everything turned freely then. Yes!

    The most annoying part of this job is getting the bearing assembly back on the forestay and getting the stay tensioned - because the turnbuckle is hidden up inside the furler bearing assembly and once you have it all together you can't get at the turnbuckle! Looking at more recent furler designs around the boatyard...this turnbuckle access problem has been solved.

    Now, my furler spins quite happily. It wasn't that bad when I compare how long I would have to work to buy a new furler and install it vs the time I spent fixing my old furler.