Replacing the Bearings on a Plastimo 608-s Furler

This one is a bit more technical; I’m posting it mainly so that if someone else needs to do this, they’ll have an idea of what it involves- I couldn’t find any information about it when I set out.

Furling is packing a sail away neatly, and a roller furler does this very well- simply by pulling a line from the cockpit, one can roll up one’s headsail, either to make it smaller if it’s too windy, or to put it away altogether. This rolling means there are bearings so it can turn smoothly, and the bearings on mine had seized (in no small part because they were regular old non-stainless steel, and this is a boat, that goes on the water). Anyway, the manual lists the halyard swivel (which goes at the top of the sail) and the drum (at the bottom) as sealed, non serviceable units, but everything is serviceable if the cost of replacement is high enough.

The swivel and the drum have two bearings each. I was able to get the drum apart at the boat, and found that one bearing was still moving, and one was frozen up. I sprayed the frozen one with penetrating oil and wrapped it in paper, hoping it might free up.

Taking the drum apart. The piece that I am holding is the end of the forestay, the wire that holds the mast up.

The halyard swivel was frozen, but I’d read online (wrongly, it turned out) that the bearings were delrin and stainless steel, so I thought they’d come loose with a good soak in some fresh water. When water didn’t help, I tried more penetrating oil, and that freed it right up- except I realised that it wasn’t the bearing turning against itself, it was frozen but had come loose from the plastic housing. It wasn’t possible to dismantle the swivel at the boat, so I took it down to the workshop.

The important thing when removing bearings is to keep the pressure axially in line with the bearing. A slight angle to either side will cause it to jam, so I needed to be able to press straight down in line with everything. The swivel assembly was a rather awkward shape, so first I had to make some wooden forks to spread the load. I did that by drilling an appropriately sized hole and then opening up one side of it on the bandsaw.

Fortunately the drill press is next to the bandsaw so I only needed to take one picture

The swivel in the press- you can see why I needed to make the forks to press it apart

This allowed me to press straight down, with even pressure across the assembly.

As you can see from the pictures, I have a little 2 tonne arbour press which is just the job for something like this. If you don’t have one, though, this setup could also be used with a hammer or mallet, though you’d also need a bit of pipe of an appropriate size to slide over the assembly for some steps.

This got the assembly apart, and you can see the two bearings are both pretty rusty. There was also an O ring seal at either end of the unit, both of which which had perished.

Using non stainless bearings in this part was not a good decision by Plastimo.

The forks I made to get the assembly apart had a 60mm hole, and now to remove the bearings themselves I needed to make another one with a 45mm hole. With the bearings removed, I measured them- the drum bearings were 65x85x10mm (that’s internal diameter, external diameter, thickness) and the swivel ones were 45x58x7mm. I ordered stainless steel ball bearings from simplybearings.co.uk- parts W618132RS and W618092RS respectively- in addition to two 54x3mm nitrile O ring seals. You could use carbon steel bearings, as Plastimo did, for around half the cost, but that seemed a bit silly. Compared to the cost of a new furling system, it makes sense to use stainless.

To press the bearings into place it was necessary to make another 45mm fork, and after that they went together pretty easily. First the O ring goes on, then the lower seal. Then you press the housing into place, and then the upper bearing and its O ring. On my cousin’s advice, I put a little silicone grease on the O rings, and it was also necessary to use some superglue on the outsides of the bearings to hold them in place in the housing.

The new stainless bearings in place. In fact, you don’t want it to look like this, you put the lower bearing on first, then the housing, then the upper bearing.

As you can see from the above, in addition to being stainless, the new bearings are also sealed, so they should hold up much better than the original carbon steel ones.

The drum, which goes at the bottom of the furler, is similar- two ball bearings, a bit bigger than those in the halyard swivel. The bearings were also more expensive, so I elected to keep the one that was still free, and replace the rusted one.

I had to make another pressing fork, this one with a hole of 65mm.

I pressed the bearings onto the centre of the drum in the workshop, and then took the drum back to the boat, where I repacked the original unsealed bearing with marine grease (I’d previously soaked it in acetone to get rid of as much of the old grease as possible). It then slid into place without needing to be pressed, though the assembly does remove from the foil if that’s necessary for you. There are two more seals in the drum, I think 65x3mm, but I didn’t need to replace them so I didn’t measure.

The drum opens with four long M5 bolts, and the nyloc nuts on mine needed replacing. Before putting the bearing assembly in, make sure to put the four shorter bolts through the holes in the base. These attach the stainless cage and forks to the bottom. Then be careful not to push them back through as you slide the forks on.

All done! Hopefully it should last a good while longer than the original setup did.