sgr143
Well-Known Member
Ours was very “lumpy” when rotated by hand; if twisted hard, it would thump between angles about 30 degrees apart, with the whole foil twanging above. Immediate diagnosis: a failed bearing, probably in the drum somewhere, maybe at the bearing at the top of the foil. Much searching on the web gave no information about how to set about checking and servicing a rotostay 2. In the end, I went about the job by improvised engineering and educated guesswork. It was successful. So here is how to do it. Hope it might be of some use to someone, somewhere, sometime...
We had the mast taken down. Having done the job, I now think you could easily manage without doing this, simply by taking up the forestay tension with a halyard and knocking out the pin holding the bottom of the forestay in place, and then proceeding with the forestay and foil still attached at the top. But we weren’t sure about what would be involved, we weren’t sure that the problem was in the drum rather than up at the top, and anyway had various mast-head jobs to do. So we have no regrets about having the mast lowered, even though it cost money.
There is a plastic drum attached to the bottom of the foil at one end, and with a screw tensioner poking out of the other. First: the little Allen bolt at the bottom of the foil has nothing to do with this job (I took a while to realise this). I don’t know what it does, but you can leave it in place.
1) Fully unscrew the forestay tensioning screw (LH thread), and remove it, so that what you are about to take off can slide easily over what is left in place (assuming it’s got a clevis or other fitting attached that will otherwise get in the way of what is to follow). You might usefully mark how far it was screwed in, to help with getting the forestay tension right on reassembly; in our case it was pretty clear because of colouration of the threads.
2) Take out the Allen bolt that holds the furling line guide and drum side-cover plates in place, and slide the guide off. (Now put the Allen bolt back in, so it doesn’t get lost!)
3) Take any remaining line off the drum.
4) You should now be able to see a black plastic pin, about 8mm diameter, that passes, off-axis, side to side through the centre of the drum. In our case it was hidden way under some insulating tape. (Hmmm. What’s under here… Aha!)). Knock it through the drum (I used a screwdriver as a drift) and you can now slide the drum off the bottom of the forestay. Pop the plastic pin back where it came from, for safe keeping.
5) The inner workings are now exposed. At one side of the foil end of the main bearing housing is a grub screw with a hex head. Unscrew this (RH thread). Now unscrew the housing (RH thread) from the lower end of the foil. Ours came off easily by hand. Pop the grub screw back in place to stop it getting lost.
At this point you have something that can be taken away to dismantle in the comfort of your own garage, workshop or kitchen: the bearing housing from which emerges the female end of the forestay tensioner. The two parts are held together by a substantial bolt.
6) There is a scroll pin through from one side to the other of the of the female end of the forestay tensioner, passing through the big bolt, that locks the big bolt into place. Press this out.
7) Clamp the forestay tensioner in a vice and use a 13/16” socket on the bolt to unscrew it (RH thread).
8) Take the bolt right out and the tensioner (into which it was screwed) now can also be removed from the bearing housing. The bearing is now visible inside the housing. (Or in my case, the sorry remains of said bearing.)
9) Use a suitably-sized drift (I used a small socket) to tap the plastic end plate off from the lower end of the housing.
10) Use a suitably-sized drift (... small socket) through the hole where the end plate was housed to knock the bearing or its remains out from the bearing housing.
You will find the bearing is of type 51102, a thrust bearing 15mm ID, 28mm OD, 9mm thick; a type readily available for about a tenner.
Reassembly should simply be the reverse of this procedure, but I haven’t done it yet! I don’t anticipate any problems though. More later.
Steve
We had the mast taken down. Having done the job, I now think you could easily manage without doing this, simply by taking up the forestay tension with a halyard and knocking out the pin holding the bottom of the forestay in place, and then proceeding with the forestay and foil still attached at the top. But we weren’t sure about what would be involved, we weren’t sure that the problem was in the drum rather than up at the top, and anyway had various mast-head jobs to do. So we have no regrets about having the mast lowered, even though it cost money.
There is a plastic drum attached to the bottom of the foil at one end, and with a screw tensioner poking out of the other. First: the little Allen bolt at the bottom of the foil has nothing to do with this job (I took a while to realise this). I don’t know what it does, but you can leave it in place.
1) Fully unscrew the forestay tensioning screw (LH thread), and remove it, so that what you are about to take off can slide easily over what is left in place (assuming it’s got a clevis or other fitting attached that will otherwise get in the way of what is to follow). You might usefully mark how far it was screwed in, to help with getting the forestay tension right on reassembly; in our case it was pretty clear because of colouration of the threads.
2) Take out the Allen bolt that holds the furling line guide and drum side-cover plates in place, and slide the guide off. (Now put the Allen bolt back in, so it doesn’t get lost!)
3) Take any remaining line off the drum.
4) You should now be able to see a black plastic pin, about 8mm diameter, that passes, off-axis, side to side through the centre of the drum. In our case it was hidden way under some insulating tape. (Hmmm. What’s under here… Aha!)). Knock it through the drum (I used a screwdriver as a drift) and you can now slide the drum off the bottom of the forestay. Pop the plastic pin back where it came from, for safe keeping.
5) The inner workings are now exposed. At one side of the foil end of the main bearing housing is a grub screw with a hex head. Unscrew this (RH thread). Now unscrew the housing (RH thread) from the lower end of the foil. Ours came off easily by hand. Pop the grub screw back in place to stop it getting lost.
At this point you have something that can be taken away to dismantle in the comfort of your own garage, workshop or kitchen: the bearing housing from which emerges the female end of the forestay tensioner. The two parts are held together by a substantial bolt.
6) There is a scroll pin through from one side to the other of the of the female end of the forestay tensioner, passing through the big bolt, that locks the big bolt into place. Press this out.
7) Clamp the forestay tensioner in a vice and use a 13/16” socket on the bolt to unscrew it (RH thread).
8) Take the bolt right out and the tensioner (into which it was screwed) now can also be removed from the bearing housing. The bearing is now visible inside the housing. (Or in my case, the sorry remains of said bearing.)
9) Use a suitably-sized drift (I used a small socket) to tap the plastic end plate off from the lower end of the housing.
10) Use a suitably-sized drift (... small socket) through the hole where the end plate was housed to knock the bearing or its remains out from the bearing housing.
You will find the bearing is of type 51102, a thrust bearing 15mm ID, 28mm OD, 9mm thick; a type readily available for about a tenner.
Reassembly should simply be the reverse of this procedure, but I haven’t done it yet! I don’t anticipate any problems though. More later.
Steve
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